My current research interest focuses on mechanobiology of cardiovascular diseases. Our group has demonstrated the first quantitative approach to changes in intravascular shear stress (ISS) with vascularoxidative stress in New Zealand White (NZW) rabbit and swine models. We have demonstrated that spatial (/x) and temporal (/t) variations in shear stress modulate post-translational oxidative modifications of low density lipoprotein protein (LDL) and mechano-signal  transduction of mitochondrial redox states. These findings led to our first joint textbook for the field of mechanotransduction entitled “Hemodynamics & Mechanobiology of Endothelium”.  By deploying micro-electromechanical systems (MEMS) sensors, we have demonstrated that the integration of ISS and electrochemical impedance spectroscopy (EIS) identifies pre-atherogenic lesions associated with oxidative stress in fat-fed NZW rabbits. We have further revealed that spatial (/x) and temporal (/t) variations in shear stress modulated oxidative stress of pro-inflammatory substrates; namely,  oxidation of low density lipoprotein protein (LDL) and formation of macrophages/form cells. These findings led to the  observation that oxidized lipids and macrophages caused distinct electrochemical properties in the vessel wall that can be measured by EIS. In this context, we are seeking to (1) characterize lipid-rich lesions via electrochemical impedance spectroscopy, (2) integrate shear stress (ISS), ultrasound (IVUS), and electrochemical impedance (EIS) for detection of lesions prone to rupture, and (3) determine the in vivo risk of rupture in high EIS plaque experienced high shear stress in a swine model.

Our laboratory has been inspired by the developmental biologists for their seminal contribution to

cardiovascular medicine using the zebrafish heart system. In collaboration with Dr.  Ellen Lien (CHLA), Dr. Neil Chi (UCSD), and Dr. Shung (USC NIH Ultrasonic Transducer Resource Center), we have developed micro-ECG approached to assess electrical phenotypes in regenerating zebrafish hearts, and we have incorporated pulsed-wave Doppler to assess electromechanical coupling of myocardium in real-time. In collaboration with Dr. Chih-Ming Ho (UCLA), we are further developing time-dependent 3-D imaging (x, y, z, t) to elucidate the mechanotransduction mechanisms underlying cardiac

 morphogenesis. Our joint efforts have demonstrated the use of zebrafish system formechanotransduction and electromechanical coupling in injured and regenerating hearts.