Scaffolding as a Platform for Cell Delivery for Abdominal Aortic Aneurysm Therapy
by Amanda Chase, PhD
January 4, 2022
Abdominal Aortic Aneurysm (AAA) is diagnosed in about 200,000 individuals in the US per year, and that number increases in older men. The aorta carries blood away from the heart. When the wall of the aorta weakens, the wall gradually bulges. That bulging is referred to as an aneurysm. If the bulge becomes too large, it can burst, which can be life-threatening. For now, AAAs are monitored for size and growth rate. Those that are small enough are simply monitored until they become large, and those that grow too quickly or that become large are surgically repaired. Currently, there are no targeted drug therapies to limit progression. Targeted treatment to decrease progression or improve the aneurysm would therefore have a profound impact on the lives of patients with AAA.
AAAs occur when the artery becomes weaker because of the loss of smooth muscle cells (SMCs) that help the aorta contract, along with degradation of the extracellular matrix (ECM) components. An attractive AAA therapy, therefore, is to regrow and deliver parts of the cell and ECM components. A group of CVI member researchers, led by first authors Joscha Mulorz and Mahdis Shayan and senior author Ngan F. Huang, recently highlighted a promising means of cell delivery to serve as a therapeutic strategy for AAA treatment. Their findings were published in Biomaterials Science.
Overview of cell-seeded scaffold on the aortic aneurysm. The scaffold with cells was implanted onto an AAA (D) and a protective cover was added (E).
In this study, they looked at delivering induced pluripotent stem cell (iPSC)-derived SMCs or primary human SMCs using a collagen scaffold (a delivery vehicle that also provides ECM cues for cell survival). An injection cannot be used because the site of an aneurysm is already weakened, and the injection can risk rupturing the aneurysm. Using a mouse model, they were able to show that primary SMCs delivered by these scaffolds was feasible and could decrease the rate of aneurysm expansion. This technique has potential for the future of slowing AAA disease progression using a minimally invasive procedure.
Other CVI member authors include Alex Chan, Joshua Spin, and Philip Tsao. Other Stanford University or Veterans Affairs Palo Alto affiliated authors include Caroline Hu, Cynthia Alcazar, Mason Briggs, Yan Wen, and Bertha Chen. San Jose State University researchers also participated in this study.
Mahdis Shayan, PhD
Joscha Mulorz, MD
Ngan Huang, PhD