Preadipocyte seeded PLGA scaffolds for adipose tissue engineering

Adipose tissue equivalents have not been addressed as yet despite the clinical need in congenital deformities, posttraumatic repair, cancer rehabilitation, and other soft tissue defects. Preadipocytes were successfully harvested from rat epididymal fat pads of Sprague-Dawley and Lewis rats and expanded ex vivo. In vitro cultures demonstrated full differentiation of preadipocytes into mature adipocytes with normal lipogenic activity. The onset of differentiation was well-controlled by regulating preadipocyte confluency. Poly(lactic-co-glycolic) acid (PLGA) polymer disks with 90% porosity, 2.5 mm thick, 12 mm diameter, pore size range of 135-633 μm were fabricated and seeded with preadipocytes at 10⁵ cells/mL. Disks in vitro demonstrated fully differentiated mature adipocytes within the pores of the disks. Short-term in vivo experiments were conducted by implanting preseeded disks subcutaneously on the flanks of rats for 2 and 5 weeks. Histologic staining of harvested disks with osmium tetroxide (OsO₄) revealed the formation of adipose tissue throughout the disks. Fluorescence labeling of preadipocytes confirmed that formed adipose tissue originated from seeded preadipocytes rather than from possible infiltrating perivascular tissue. This study demonstrates the potential of using primary preadipocytes as a cell source in cell-seeded polymer scaffolds for tissue engineering applications.