title: Quantification of cardiomyocyte contraction based on image correlation analysis.
abstract: Quantification of cardiomyocyte contraction is usually obtained by measuring globally cell shortening from the displacement of cell extremities. We developed a correlation-based optical flow method, which correlates the whole-cell temporal pattern with a precise quantification of the intracellular strain wave at the sarcomeres level. A two-dimensional image correlation analysis of cardiomyocytes phase-contrast images was developed to extract local cell deformations from videomicroscopy time-lapse sequences. Test images, synthesized from known intensity displacement fields, were first used to validate the method. Intracellular strain fields were then computed from videomicroscopy time-lapse sequences of single adult and neonatal cardiomyocytes. The propagation of the sarcomeres contraction-relaxation wave during cell contraction has been successfully quantified. The time-varying patterns of intracellular displacement were obtained accurately, even when cardiomyocyte bending occurred in pace with contraction. Interestingly, the characterization of the successive 2D displacement fields show a direct quantification of the variation with time of intracellular strains anywhere in the cell. The proposed method enables a quantitative analysis of cardiomyocyte contraction without requiring wave tracking with the use of fluorescent calcium probes. Thus, our algorithmic approach provides a fast and efficient tool for analyzing the correlation between global cell dynamical behavior and mechanosensitive intracellular processes.
authors.affiliation: Equipe DynaCell, Laboratoire TIMC-IMAG, UMR CNRS 5525, Institut de l'Ingénierie et de l'Information de Santé, (In3S), Faculté de Médecine de Grenoble, 38706 La Tronche Cedex, France.
authors.forename: A
authors.initials: A
authors.lastname: Kamgoué
authors.forename: J
authors.initials: J
authors.lastname: Ohayon
authors.forename: Y
authors.initials: Y
authors.lastname: Usson
authors.forename: L
authors.initials: L
authors.lastname: Riou
authors.forename: P
authors.initials: P
authors.lastname: Tracqui
mesh_terms: D000465:Algorithms; D000818:Animals; D000831:Animals, Newborn; D002478:Cells, Cultured; D006321:Heart / Q000033:anatomy & histology / Q000254:growth & development; D019044:Image Cytometry / Q000379:methods*; D008858:Microscopy, Phase-Contrast / Q000295:instrumentation / Q000379:methods; D018715:Microscopy, Video / Q000295:instrumentation / Q000379:methods*; D009119:Muscle Contraction / Q000502:physiology*; D009206:Myocardium / Q000166:cytology*; D032383:Myocytes, Cardiac / Q000166:cytology* / Q000502:physiology*; D051381:Rats; D012518:Sarcomeres / Q000502:physiology / Q000648:ultrastructure; D012984:Software; D013314:Stress, Mechanical; D013997:Time Factors