April 15, 2008 10-12 (Tuesday)

Multiscale Modeling of Calcium Dynamics in Ventricular Myocytes: 
from Imaging to Simulation

Dr. Zeyun Yu, University of California, San Diego

Abstract
Intracellular calcium has been found to be the central regulator of
cardiac cell contractions. Modeling calcium dynamics is hence
fundamental in understanding the excitation-contraction (E-C) coupling
in cardiac myocytes. Both experimental and computational studies have
revealed that the geometry of calcium-regulating organelles, such as
transverse-tubules (T-tubules) and junctional sarcoplasmic reticulum
(jSR), can significantly affect the calcium dynamics, suggesting that
3D structures from imaging data would provide more realistic modeling
of the E-C coupling mechanism.

To bridge the gap between imaging and simulation, I shall present a
chain of image analysis and geometric processing approaches to
constructing multiscale models of ventricular cells. In particular,
two imaging techniques are considered: one is the two-photon
laser-scanning microscopy imaging at the micro-scale, and the other is
the electron tomography imaging at the nano-scale. Accordingly, 3D
realistic geometric models of T-tubular systems and individual calcium
release units (CRUs) are computed from the imaging data and
represented by high-quality surface and volumetric meshes. Both
stochastic (Monte-Carlo based) methods and deterministic (PDE-based)
numerical approaches are utilized to simulate calcium release,
buffering, and diffusion in ventricular myocytes.


Bio:
Zeyun Yu is currently a postdoctoral fellow of the National
Biomedicine Computation Resource (NBCR), working jointly in Department
of Mathematics and Department of Chemistry & Biochemistry at
University of California, San Diego. He received the B.S. degree in
Mathematics from Peking University (Beijing, China) in 1996 and the
M.S. degree in Pattern Recognition and Machine Intelligence from
Chinese Academy of Sciences (Beijing, China) in 1999. He was awarded
the Ph.D. degree in Computer Science from The University of Texas at
Austin in 2006. His research interests span from algorithms in image
analysis, pattern recognition, numerical simulation, and 3D
visualization, to applications in structural and functional modeling
of biomedical systems.