ERI: Biological Effects of Low-Frequency, Low-Intensity Ultrasound on Endothelial Cell and Macrophage Co-Culture

This Engineering Research Initiation (ERI) award will support research to investigate the effects of ultrasound on endothelial cells (blood vessel cells) and macrophages (immune cells). Endothelial cells and macrophages work together in many biological processes, one of which is angiogenesis, the creation of blood vessels. Angiogenesis is critical for the healing of damaged tissues as in the case of chronic wounds. Chronic wounds last on average twelve months and may lead to amputation of lower limbs or possibly even death. Human clinical trials have shown that low-frequency, low-intensity ultrasound advances chronic wound healing. However, the biological mechanisms are still not understood. The knowledge gained from understanding how ultrasound affects endothelial cells and macrophages individually and together may enhance ultrasound therapies for advanced healing and ultimately increase the quality of life for patients. This award will also promote undergraduate and high school student exposure and training in tissue engineering, particularly for underrepresented students and women in engineering through hands-on laboratory experiences. Formal course offerings in tissue engineering will also be developed for both engineering and non-engineering majors with a focus on minoritized students and women in engineering. The research goal is to evaluate the promotion of angiogenesis as a possible biological mechanism of therapeutic ultrasound. This will be achieved through two objectives: (1) characterize uni- and bi-directional effects of low-frequency, low-intensity ultrasound on macrophage and endothelial cell pro-angiogenic factors via macrophage and endothelial direct co-culture, indirect co-culture (transwell), and individually (endothelial alone and macrophage alone) and (2) analyze gene expression changes using bulk RNAseq and global bioinformation methods. These objectives will be conducted in vitro using 3D collagen scaffolds to more closely mimic physiological conditions. Understanding the effects of therapeutic ultrasound on angiogenesis will provide insight to the possible biological mechanisms of ultrasound. Preliminary data and published literature strongly suggest that stimulation of angiogenesis may be the mechanism through which ultrasound mediates healing. If this is confirmed by the data collected, this may indicate that ultrasound could be an effective therapy to recover functional endothelial behavior where pathological angiogenesis is a hallmark of diseases including atherosclerosis, rheumatoid arthritis, and autoimmune diseases. These data would provide insights into novel therapeutic applications of ultrasound. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.