Mechanical and Mechanobiological Factors in Aneurysm Progression

Friday, January 15, 2016, 3:00 pm

Sidney & Marian Green Classroom (3550 MEK)
Reception to follow at 4:00 pm

Jay D. Humphrey, Ph.D.
Professor and Chair of Biomedical Engineering
Yale University

Abstract: Aneurysms are local dilatations of the arterial wall that are responsible for significant disability and death. Notwithstanding the importance of biological factors, the ultimate fate of these aneurysms (rupture) depends directly on the mechanics. In this presentation, we will examine issues relating to both intracranial and aortic aneurysms from the perspective of continuum and computational biomechanics: Why do they enlarge? Why do they rupture? Toward this end, we will consider issues ranging from standard stress analyses to dynamical stability and processes of biological growth and remodeling.

Bio: Jay Humphrey received his BS in Engineering Science & Mechanics from Virginia Tech, Blasksburg, VA in 1981, his MS in the same field at Georgia Institute of Technology, Atlanta, GA in 1982, his Ph.D. also from Georgia Tech in 1985 in the area of applied mechanics/bioengineering, and a post-doc in 1987 at Johns Hopkins University in cardiovascular biomechanics.

Humphrey has 30 years of experience in the field of continuum biomechanics, with primary interest in vascular mechanics and mechanobiology. His lab has considerable experience in the design and construction of novel computer-controlled multiaxial test systems, measurement of vascular mechanical properties, computer-aided histological characterizations, nonlinear constitutive formulations, measurement of in vivo hemodynamics, and computational biomechanics (mainly finite elements). They have formulated a unique “Constrained Mixture Theory” for arterial growth and remodeling (G&R) that has provided significant insight into the biomechanics of arterial adaptations to altered hemodynamics as well as aneurysmal enlargement, vein graft maladaptation, and tissue engineered vascular graft development.

They have also developed both a finite element model of the effects of pooled glycosaminoglycans within the aortic wall, a histopathological characteristic unique to thoracic aortic aneurysms and dissections, and a fluid-solid interaction model of the aortic tree that enables hypothesis generation and testing as well as experimental design. Given that intraluminal and intramural thrombosis play important roles in many vascular conditions, they have also developed growth and remodeling models of thrombus initiation, progression, and remodeling.

Finally, Humphrey’s lab has considerable experience with rodent models of vascular disease, including genetically modified, pharmacological, and surgical. He recently published, for example, a first of its kind comparative biomechanical phenotyping of common carotid arteries from seven different mouse models that suggested that mural cells attempt to maintain material stiffness constant.

The Department of Mechanical Engineering at the University of Utah is committed to providing students with broad-based, rigorous and progressive education. By combining state-of-the-art facilities with renowned faculty, the department provides an education that gives students the necessary skills to become the next generation of innovators.