Abstract
BACKGROUND: Mechanical processing of lipoaspirate (LA) produces a stromal vascular fraction (SVF) without enzymatic digestion for use in aesthetic, surgical, and regenerative applications. We recently presented novel device technologies that increased mesenchymal stem cell (MSC) content relative to standard nanofat (NF) processing. OBJECTIVES: Here, we introduce a third technology designed to enhance fluid shear forces and explore the impact of mechanical processing on regenerative potential in vitro. METHODS: Human LA samples were processed with our previously reported emulsification micronization device and filtration device, and then optimized using a new shearing device (SD). Results were analyzed for total cell count, viability, and percentages of endothelial progenitor cells (EPCs) and MSCs compared to manual NF processing, both immediately and following 24-hour culture. Expression of genes related to wound healing was quantified by real-time quantitative polymerase chain reaction, and angiogenic capacity was determined with an in vitro 3-dimensional sprouting assay. RESULTS: The SD did not significantly affect MSC recovery or viability, but EPCs were enriched in a shear stress-dependent manner. Gene expression was not altered immediately after processing, but after culture we noted changes to wound-healing transcriptional programs that were consistently stronger for our devices than NF. Differences were statistically significant for CXCL1, IL1β, IL6, CSF3, and COL1A2. Notably, angiogenic vessel sprouting was significantly enhanced for our devices compared to NF. CONCLUSIONS: Mechanical processing of lipoaspirate with our 3-device platform resulted in greater enrichment of stem and progenitor cells, activation of genes implicated in wound healing, and induction of angiogenesis in vitro relative to NF. Future studies will ascertain potential implications in vivo for all indications that currently utilize NF, as well as automate the process within an integrated system.