Creating More Durable, Small Vascular Grafts

Patients with vascular disease frequently experience blockage in the arteries that cause poor blood flow. Often, physicians bypass the blood flow around the blockage using vascular grafts, either by using the patient’s veins from another part of the body or using synthetic grafts. Both methods present their own limitations.


“If a patient has a lot of vascular disease, these replacement vessels may not make the strongest choice for a bypass or provide enough material for bypassing all the blockages,” says Aaron Baker, an associate professor in the Department of Biomedical Engineering. “If you’re taking a vein from the leg of someone who already has bad vasculature, that vessel may also have disease or may close again over a relatively short time.”

The other option, using synthetic grafts made from materials such as Teflon, work well for large diameter grafts but do not work for the smaller graft sizes that are often needed.

Baker has recently received a new four-year R01 grant in the amount of $1.565 million from the National Heart, Lung, and Blood Institute (NHLBI) to create better quality grafts, which would retain healthy blood flow longer and present a more durable solution for patients. Baker’s lab uses a process called decellularization, where an extracellular matrix scaffold is isolated from a tissue. This scaffold of the original tissue can then be used with mesenchymal stem cells harvested from the bone marrow to create a graft using the patient’s own cells.

To induce the mesenchymal stem cells to perform as vascular cells, Baker’s lab is using a unique combination of applied mechanical forces and drug screening. This multifaceted approach, in which the efficacy of different drugs is monitored while mechanical forces are applied, allows for more patient-specific graft creation.

“Part of the project will be to test out the personalized medicine aspect that this system could enable,” Baker says. “The screening system is blind to what type of cell we’re using, which means we should be able to do a drug screen to find the right drug for you, for me, and for someone who has had diabetes for 40 years.”

This personalization is important because mesenchymal stem cells vary between individuals. The cells’ regenerative properties are especially diminished in patients with diabetes, who are frequent candidates for vascular grafts.

For this project, Baker’s lab works is collaborating with Brian Cooley, an associate professor from the University of North Carolina School of Medicine, Michael Sacks, professor of biomedical engineering and director of the Willerson Center for Cardiovascular Simulation at UT Austin, and Richard Smalling an interventional cardiologist from the McGovern Medical School at UT Health Science Center in Houston.