10 | Human myogenic progenitor and 3D bioprinting for volumetric muscle loss recovery in swine model

Rebecca Deodati, F. De Paolis, E. Guarnaccia, B. Corci, S. Bernardini, M. Costantini, C. Fuoco, C. Gargioli | Dept. of Biology, University of Tor Vergata, Rome, Italy.

Volumetric muscle loss (VML) poses a clinical challenge due to the native skeletal muscle's inability to regenerate large tissue defects, often resulting in fibrosis and functional impairment. Despite various approaches, current therapeutic strategies fail to provide a fully effective and durable solution for VML, highlighting the need for innovative regenerative treatments. This study aims to explore the regenerative potential of primary human pericytes embedded in 3D-bioprinted constructs for VML treatment using a swine model. Human pericytes, isolated from muscle biopsies and characterized through immunofluorescence and flow cytometry, demonstrated strong myogenic potential, making them excellent candidates for use. Pericyte-laden hydrogel constructs, fabricated using a custom microfluidic-assisted 3D rotary wet-spinning (RoWS) bioprinting platform with and without an alginate shell, were surgically implanted into an induced VML site in mini-pig limbs. Over a period of 120 days, tissue regeneration was monitored via ultrasound imaging, histological staining, and immunofluorescence analysis of biopsies. Results indicated that constructs containing alginate maintained greater structural integrity over time, promoting vascularization and a more compact tissue architecture. PAN-positive human cells were detected in the biopsies, confirming the survival of implanted pericytes. Myogenic differentiation was evident only at 60 days post-implantation, with the emergence of small fibers. Furthermore, a progressive reduction in macrophage infiltration (MannRpositive area) suggested a resolution of inflammation possibly associated with active tissue remodeling. This work demonstrates that human pericytes, when delivered through a biocompatible 3Dprinted scaffold, can survive in vivo, support neovascularization, and initiate myogenic differentiation in a large animal VML model, offering a promising avenue for translational muscle regenerative therapies.