AVS 46th International Symposium
    Biomaterial Interfaces Group Tuesday Sessions
       Session BI-TuP

Paper BI-TuP9
The Role of Angiogenesis at Biomaterial Interfaces

Tuesday, October 26, 1999, 5:30 pm, Room 4C

Session: Poster Session
Presenter: P.C. Stephans, University of Washington
Authors: P.C. Stephans, University of Washington
R.B. Vernon, Hope Heart Institute
E.H. Sage, Hope Heart Institute
P.S. Stayton, University of Washington
Correspondent: Click to Email
When a biomaterial is implanted, a relatively avascular fibrotic layer forms around the device. For devices such as sensors, this can inhibit the proper function of the device because the sensor only samples the microenvironment of the capsule. However, if the vascularity of the tissue adjacent to the device is increased, then the sensor can continue sampling a more representative environment. This problem has led to an interest in angiogenesis, the growth of new blood vessels from an existing vasculature, and how it is altered by various material properties. We are studying three material factors that may affect angiogenesis. The first, porosity, is based upon previous in vivo work that demonstrated a correlation between porosity and the number of vascular structures located close to the material. The second is coating the material with molecules, such as extracellular or matrix proteins. For example, we are currently immobilizing a peptide from SPARC that has shown angiogenic activity in vivo. The third factor is the release of soluble agents in the context of a material. Various soluble factors have been identified that are angiogenic, but now we can study the factor release from a material to determine if the angiogenic response can be stimulated within the material. To facilitate these studies, we are developing in vitro assays to study angiogenesis in the context of a biomaterial. For example, we have developed an assay to measure migration, a crucial step in angiogenesis. A teflon fence is used to grow endothelial cells to confluence in a well-defined area on the material. Once the fence is removed, the migration on various surfaces can be measured. The macrophage, a key player in angiogenesis, can also be incorporated into the assay to determine the effect of cytokine secretion on the endothelial cells. By studying the materials with these assays, we hope to gain a better understanding of the cell-material interactions that guide angiogenesis.