David Bark, assistant professor of mechanical engineering in the Walter Scott, Jr. College of Engineering, was recently announced as the recipient of the American Heart Association (AHA) Career Development Award. The award supports “highly promising healthcare and academic professionals, in the early years of one’s first professional appointment, to explore innovative questions or pilot studies that will provide preliminary data and training necessary to assure the applicant’s future success as a research scientist in the field of cardiovascular and stroke research.”
Bark’s AHA Award will focus on investigating the underlying biophysical mechanisms leading to ischemia reperfusion injury (IRI), a complication in a wide range of conditions including heart attack, ischemic stroke, and organ transplantation. In these conditions, the primary goal is to reintroduce blood flow to the ischemic tissue, which can paradoxically increase the tissue damage caused by initial ischemia. Bark’s prior work suggests that the increased damage may in part result from the changes to biophysical interactions between blood cells in response to biochemical changes that occur during reperfusion after an ischemic event. Bark and his team will combine laboratory experiments in microfluidic devices with computational modeling to further elucidate these mechanisms that lead to IRI.
BIOLOGICAL IMPACTS OF THE MECHANICAL ENVIRONMENT
Bark’s interest in blood cells extends to the response of platelets to their local mechanical environment as a result of flow. Platelets are the cells that help to stop bleeding after injury by forming adhesive bonds to other parts of the blood and body, a process commonly known as clotting. While the biochemical signals governing clotting have been intensely studied, it is unknown whether cellular sensing of mechanical forces is important in the ‘decision’ of a platelet to participate in clotting. Bark has recently been awarded a $408,048 grant from the National Science Foundation to study how platelets respond to mechanical loading, and how that response helps regulate hemostasis and thrombosis. These processes play a fundamental role in the initiation of a heart attack or stroke.
Bark and his team are currently completing a project funded by a one-year pilot grant from the Colorado Clinical and Translational Sciences Institute to study the potential role of the mechanical environment in congenital heart defects (CHD). In collaboration with cardiologists at Children’s Hospital Colorado, Bark and his team are analyzing the four-dimensional flow field in fetal hearts through ultrasound imaging and flow modelling. Flow-induced stress experienced by cardiovascular cells will be studied to determine whether and how the fluid mechanical environment can influence heart morphology during development. The results from this study are anticipated to help guide the development of prophylactic treatments for CHDs.
Bark and his team are further collaborating with Deborah Garrity from the Department of Biology at Colorado State University, where they are further testing the role of mechanics in the formation of CHD in an embryonic zebrafish model through a project funded by the American Heart Association, where Bark is serving as a co-investigator.
HEMOCOMPATIBILITY in MEDICAL DEVICES
Bark’s postdoctoral research was supported by a National Institutes of Health (National Heart Lung and Blood Institute) F32 Ruth L. Kirschstein National Research Service Award Individual Postdoctoral Fellowship, “Biomechanical Response of Platelets to Superhydrophobic Surface in Mechanical Heart Valves and Other Blood-Contacting Medical Devices.” Bark investigated the hemodynamic and hemocompatibility characteristics of various options for replacement heart valves: polymeric valves, coated mechanical valves, and textile valves. He showed that the best hemodynamics depend on flexible valves and the properties that define the valves. Hemocompatibility increased for hydrophilic surface designs and for valves coated with superhydrophobic layers. Results are being applied by Bark and collaborators to the development of a number of promising prosthetic valves that overcome the limitations of current FDA-approved devices. These efforts have led to an R01, funded by the National Heart Lung and Blood Institute, where Bark is serving as a co-investigator.
THE BARK LAB
David Bark is an assistant professor of mechanical engineering in the Walter Scott, Jr. College of Engineering at Colorado State University, and also holds an appointment in the School of Biomedical Engineering. Bark and his group conduct research in cardiovascular biomechanics and mechanobiology, with a focus on hemostasis and thrombosis, heart development, and the development of medical devices.
Bark earned his Ph.D. in bioengineering and M.S. in mechanical engineering from the Georgia Institute of Technology, and completed his B.S. in mechanical engineering at the University of Illinois at Urbana/Champaign. Bark’s postgraduate professional experience includes research fellow positions at the University of Canterbury in Christchurch, New Zealand, and the Australian Centre for Blood Diseases at Monash University in Melbourne, Australia; postdoctoral fellow in the Department of Mechanical Engineering at Colorado State University; and postdoctoral fellow in the Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, CO, where he holds an appointment as adjunct assistant professor. His postdoctoral research was supported by a National Institutes of Health (National Heart Lung and Blood Institute) F32 Ruth L. Kirschstein National Research Service Award Individual Postdoctoral Fellowship.
“By leveraging natural cellular responses to a mechanical environment, it may be possible to better target diseases of the cardiovascular system.”
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School of Biomedical Engineering: Medical Devices and Therapeutics
The Colorado State University School of Biomedical Engineering (SBME) provides transdisciplinary education, research, and practical experiences throughout a full range of degree programs. The unique structure of the School involves four colleges, 14 departments, and over 70 faculty.
Research interests of the faculty involved in the Medical Devices and Therapeutics theme in SBME include biomedical image and signal processing, cardiovascular mechanics, equine orthopedics, and polymeric biomaterials.