Freshly isolated stromal cells from the infrapatellar fat pad are suitable for a one-step surgical procedure to regenerate cartilage tissue

Background aims Stem cell therapies are being evaluated as promising alternatives for cartilage regeneration. We investigated whether stromal vascular fraction cells (SW) from the infrapatellar (Hoffa) fat pad are suitable forte one-step surgical procedure to treat focal cartilage defects. Methods SVF was harvested from patients undergoing knee arthroplasty (n = 53). Colony-forming unit (CFU) assays, growth kinetics and surface Walker profile's were determined, and the chondrogenic differentiation capacity of freshly isolated SVF was assessed after seeding in three-dimensional poly (L-lactic-co-epsilon-caprolactone) scaffolds. Results SVF yield per fat pad varied between 0.55 and 16x10(6) cells. CPU frequent), and population doubling time were 2.6+/-0.6% and +/-2 clays, respectively. Surface marker profiles matched those of subcutaneous-derived adipose-derived stem cells (ASC). CPU from Hoffa Stir showed differentiation toward osteogenic and adipogenic lineages. Cartilage differentiation was confirmed by up-regulation of the cartilage genes sox9, aggrecan, collagen type II and cartilage oligomeric matrix protein (COMP), collagen II immunostaining, Alcian Blue staining and glycosaminoglycan production. Compared with passaged cells, SVF showed at least similar chondrogenic potential. Conclusions This study demonstrates that SVF cells from the infrapatellar fat pad are suitable for future application in a one-step surgical procedure to regenerate cartilage tissue. SVF shows similar Pivot-able characteristics as cultured ASC, and chondrogenic differentiation even appears to be slightly better. However, because of variable harvesting volumes and yields, SVF from the infrapatellar fat pad might only be applicable fir treatment of small focal cartilage defects, whereas for larger osteoarthritic defects subcutaneous adipose tissue depot would be preferable.