3D-printed patch grows healthy blood vessels in mice, could treat ischemia

The 3D-printed patch guides the formation of new blood vessels, addressing one pitfall of therapeutic angiogenesis—the growth of a disorganized and twisted network of vessels.

A Boston University-led team has created a cell-infused 3D-printed patch that could become a new treatment option for challenging cases of ischemia.

Ischemia, where tissue or an organ does not receive enough blood—and therefore, oxygen—can result from narrowed, hardened or blocked blood vessels. Myocardial ischemia, or ischemia of the heart, can lead to complications including an irregular heart rhythm, heart attack or heart failure.

Ischemia of the heart may be treated with drugs, such as blood thinners or blood vessel relaxers, or surgical procedures, such as coronary artery bypass. However, treatment can be difficult in smaller blood vessels, or vessels that have been damaged by previous treatment, Boston University said in a statement.

Christopher Chen, director of the Biological Design Center at BU, is working on restoring blood flow to affected tissue with 3D-printed patches that promote the growth of healthy new blood vessels.

He seeks to eliminate some of the problems with therapeutic angiogenesis, an experimental treatment where growth factors are injected to foster the formation of new vessels.

“Therapeutic angiogenesis … is a promising experimental method to treat ischemia,” Chen said in the statement. “But in practice, the new branches that sprout form a disorganized and tortuous network that looks like sort of a hairball and doesn’t allow blood to flow efficiently through it. We wanted to see if we could solve this problem by organizing them.”

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The team, which includes Keith Ozaki, M.D., a surgeon at Brigham and Women’s Hospital who has expertise in leg ischemia, and Joseph Woo, M.D., of Stanford University, infused two patches with endothelial cells, which line the inside wall of blood vessels.

The researchers simply injected cells into one patch, while they organized the cells in the other patch into a “specific architecture.” They implanted the patches into mouse models of heart attack and hind limb ischemia. The organized patches reduced ischemia, while the unorganized patches resulted in a twisted mass of vessels. The research is published in Nature.

“The pre-organized architecture of the patch helped to guide the formation of new blood vessels that seemed to deliver sufficient blood to the downstream tissue. While it wasn’t a full recovery, we observed functional recovery of function in the ischemic tissue,” Chen said.

To create 3D-printed patches on a small scale, the researchers worked with colleagues at Boston-based biotech, Innolign, which Chen helped found. The team plans to test different organizations of cells to see if there is a more effective arrangement. They will also work on scaling up the technology.