The goals of the proposed research are to investigate how upstream platelet-agonist interactions affect the downstream platelet interactions with blood-contacting biomaterials. Almost all past research efforts in the field of biomaterial hem compatibility have focused on the local biomaterial surface properties. While these observations are essential for predicting a material's behavior in circulation, they do not reflect the whole story. For example, upstream suturing of a vascular graft creates an anastomosis (a surgical connection between biomaterial and native blood vessel) that has the potential to transiently expose different agonists to circulating platelets. Our preliminary experiments and mathematical modeling suggest that this upstream history of platelet-agonist interaction significantly influences plateet behavior downstream of an anastomotic site. The upstream priming effects are compounded by the fact that no blood-contacting biomaterials are perfectly hem compatible. It is hypothesized here that the magnitude of the downstream biomaterial-platelet interactions is strongly influenced by the transient platelet exposure to upstream platelet agonists that can prime platelets for adhesion and activation. Platelets exposed to agonists are thus more likely to adhere to and become activated by a downstream biomaterial than in the absence of such agonists. It is not known how far downstream these priming effects persist, how much time is required for the primed platelets to become quiescent again, and by which mechanism this phenomenon takes place. From a biomaterials point of view, this problem translates into determining the acceptable tolerance for the extent of upstream priming. In other words, even biomaterials that have very little tendency to activate platelets may do so simply because of the upstream priming of platelets. The proposed study of upstream platelet-agonist effects is expected to result in a new paradigm in the field of biomaterial-derived platelet aggregation and thrombus growth; one that is not exclusively dependent on the local biomaterial surface properties but includes upstream anastomoses and perturbed blood flow. The combination of experiments and modeling in the proposed study will provide new insight into the roles of different upstream agonists and thus has the potential for establishing predictive parameters that could be used to improve the design of blood contacting devices such as catheters, grafts, and other vascular implants.

Public Health Relevance

The transient nature of agonist-induced platelet adhesion and activation has largely been ignored in the design of vascular implants. The proposed research uses a novel approach to study how platelets interact with blood-contacting biomaterials by taking into account the history of upstream platelet- agonist contacts. The results will help develop a new paradigm for minimizing biomaterial-derived platelet aggregation and thrombus growth; one that is not exclusively dependent on the local biomaterial surface properties but also includes the role of upstream anastomoses and perturbed blood flow. It is expected that the study will establish predictive parameters that could be used to improve the design of blood contacting devices such as catheters, grafts, and other vascular implants.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL126864-03
Application #
9234584
Study Section
Biomaterials and Biointerfaces Study Section (BMBI)
Program Officer
Sarkar, Rita
Project Start
2015-04-01
Project End
2019-03-31
Budget Start
2017-04-01
Budget End
2018-03-31
Support Year
3
Fiscal Year
2017
Total Cost
Indirect Cost
Name
University of Utah
Department
Biomedical Engineering
Type
Biomed Engr/Col Engr/Engr Sta
DUNS #
009095365
City
Salt Lake City
State
UT
Country
United States
Zip Code
84112
Leiderman, Karin; Chang, William C; Ovanesov, Mikhail et al. (2016) Synergy Between Tissue Factor and Exogenous Factor XIa in Initiating Coagulation. Arterioscler Thromb Vasc Biol 36:2334-2345
Eichinger, Colin D; Fogelson, Aaron L; Hlady, Vladimir (2016) Functional assay of antiplatelet drugs based on margination of platelets in flowing blood. Biointerphases 11:029805