AUTHOR=Alwan Abdelrahman , Khalil Fatma , Bowlby Joshua , Peko Gabrielle , Estrada Exel Valle , Singh Sangeeta , Deep Gagan , Zhang Yuanyuan , Farney Alan C. , Opara Emmanuel C. TITLE=Effect of controlled release of HGF on extracellular vesicle secretion by urine-derived stem cells JOURNAL=Frontiers in Bioengineering and Biotechnology VOLUME=Volume 12 - 2024 YEAR=2024 URL=https://www.frontiersin.org/journals/bioengineering-and-biotechnology/articles/10.3389/fbioe.2024.1436296 DOI=10.3389/fbioe.2024.1436296 ISSN=2296-4185 ABSTRACT=introduction: The hepatic growth factor (HGF) stimulates DNA synthesis and cell proliferation and plays a role in tissue protection and regeneration. In this study, we have examined the effect of incubation of HGF with urine-derived stem cells (USC) on the secretion of small extracellular vesicles (sEV) by the cells. Materials and Methods: HGF in the incubation medium was either a bolus administration or a controlled release of an equivalent amount from microbeads within the size range of 50-200 µm made with ultrapurified low viscosity high-guluronic acid (UP-LVG) alginate. The incubations of USC with or without HGF were 3 days or 7 days before removal of the incubation media for harvesting sEV by precipitation method. Protein content of isolated sEV was measured by BCA assay for these three groups: control (no HGF-beads), bolus HGF, and HGF-beads. We also performed nanoparticle-tracking analysis (NTA), Western Blot assay and ELISA for HGF content of samples. Results: We found a significantly higher concentration of proteins in the HGF microbeads (control release group) compared to the bolus group and the control group after 7 days (p<0.0017). The NTA data aligned with the BCA as it showed a significantly higher concentration of particles within the size range of sEV (<200 nm) in the group treated with HGF beads compared to the two other groups on day 7 (p<0.0001). Conclusion: we found that administration of HGF to USC by controlled release of the growth factor significantly enhances the levels of sEV secretion during 7 days of incubation.