Current Research
We have several research foci:
- Myocardial/Mechanical Control of Relaxation
- Direct link to charles’s ISHR webinar information (including partial bibiolograhy)
- Ultrasound Characterization of Striated Muscle Structure and Function
- Titin
- Technique Improvements
Technique Improvement
Extending on our prior work with Ken Campbell (1 2). We’ve recently sought to improve the yield of primary isolated cardiomyocytes. Of interest, this study was inspired by a seminar of a visiting speaker (Joseph Metzger, University of Minnesota) who has described the applications of Poloxamers in membrane stability. We recently described that the acute addition of Poloxamer 188 to the initial phase of isolation can improve the quantity of rod-shaped cells (pubmed link).
Prior Work
Many of the previous projects inform our current projects. Here’s a quick summary of some of our prior work:
2012-2015 Transmural Mechanics
Work with Kenneth S Campbell, PhD (Campbell Muscle Lab at the University of Kentucky) focused on measuring cardiac properties as they differ from the epicardium (outside layer of the heart) through the muscle to the endocardium (the part of the heart that touches the blood pool). Primary work evaluated reproducibility and long-term storage of cardiomyocyte measurements. Other work included in assisting with measurements of muscle samples from clinical patients.
The current strain-rate dependent relaxation studies were also initiated during this time with significant support by Ken.
2007-2012 Diastole and the Giant Protein Titin
Work with Henk L Granzier, PhD (Sarver Heart Center, University of Arizona) focused on the largest naturally occurring protein that we know of, titin. Initial studies examined interactions between actin and the PEVK domain of titin, a highly charged section; the interaction caused a viscous interaction that could be detected in vivo. Later studies focused on how titin size impacted passive stiffness in discrete biomechanics assays and in vivo. One important finding is that shorter, stiffer titin proteins caused exercise intolerance.
2002-2007 Developing new, clinically viable indexes of Diastolic (Dys)function
Work with Sandor J Kovacs, PhD MD (Cardiovascular Biophysics Lab, Washington University in St Louis) focused on the use of Kinematic Modeling to help improve our understanding of how the heart relaxes and fills. A major work included adapting the Parameterized Diastolic Filling Formalism, developed for early filling, to isovolumic relaxation.