Ultrasound promotes blood vessel growth in damaged tissue

A dual transducer system developed at the University of Rochester organizes endothelial cells – the cells that form blood vessels – into specific patterns. These patterns encourage the formation of new vascular networks, which are crucial for restoring blood flow to damaged tissues.

"We developed a novel technique using some of the forces associated with an ultrasound field called acoustic radiation force to act on cells in a material to move them to different spatial locations," said Diane Dalecki, Professor of Biomedical Engineering at the University of Rochester and director of the Rochester Center for Biomedical Ultrasound. By adjusting the frequency of the sound fields, Dalecki and her team can control how the cells are arranged, which ultimately influences the type of blood vessel networks formed.

The research team, led by Dalecki and Denise Hocking, Professor of Pharmacology and Physiology, has successfully used this technique to engineer blood vessel networks in laboratory settings. Their next goal is to refine the process for creating new blood vessels directly within the body. This approach could prove especially beneficial in clinical applications such as wound healing and reconstructive surgeries. Ultrasound, already widely used in medical diagnostics, can penetrate tissues, making it a promising method for non-invasive treatment.

The project has received a $2 million grant from the National Institutes of Health to advance these technologies. The first step in the process involves determining the ideal combination of cells and hydrogels that will best support the formation of new blood vessels. The research team aims to avoid the lengthy process of extracting stem cells from bone marrow and instead plans to use cells derived from the patient's fat tissue.

Additionally, the researchers are developing new instrumentation to enable the procedure within the body. While previous methods used a transducer and a reflector outside the body, this approach is not feasible for in vivo applications. Instead, the team is testing alternative methods, including a holographic lens transducer with a 3D-printed mask and two intersecting ultrasound beams to create an acoustic standing wave field.

The ultimate goal of the research is to demonstrate the effectiveness of the procedure in a clinically relevant model. The technology could eventually be applied in various medical fields, including plastic and reconstructive surgeries, cancer surgeries, and ischemic injuries, which involve tissue death due to a lack of blood supply.

According to Hocking, "During reconstructive surgeries such as after a tumor removal, you've taken out a lot of tissue and you can replace it with a filler, but there are no blood vessels. As a result, a lot of people have a loss of blood vessels in surrounding tissue - what we call an ischemic injury. That leads to cell and tissue death in the area. We want to be able to reconstruct some of those small microvessels to restore good blood flow and preserve the tissue."

MEDICA-tradefair.com; Source: University of Rochester