ABSTRACT
BACKGROUND: Liposuction-derived stem cells (processed lipoaspirate) have recently been shown to be capable of differentiating into bone. Most studies on osteoblastic growth and differentiation have been conducted in a conventional two-dimensional culture system; however, in native bone, osteoblasts are situated in a three-dimensional configuration. There have been limited studies of processed lipoaspirate behavior in three-dimensional systems. The authors studied the influence a three-dimensional scaffold has on the expression of genes related to osteogenesis and angiogenesis in processed lipoaspirate cells. METHODS: One million processed lipoaspirate cells were seeded onto two-dimensional poly(l-lactide-co-glycolide) films or in three-dimensional poly(l-lactide-co-glycolide) scaffolds and incubated in osteogenic medium up to 21 days. RNA was extracted and analyzed with quantitative real-time polymerase chain reaction. RESULTS: When an inert three-dimensional poly(l-lactide-co-glycolide) scaffold was introduced, the pattern and sequence of gene expression changed significantly. Processed lipoaspirate cells cultured onto three-dimensional scaffolds had increased expression of interleukin-8 and vascular endothelial growth factor compared with two-dimensional controls at early time points. Osteogenesis markers-alkaline phosphatase, collagen type I, osteocalcin, osteonectin, and osteopontin-were significantly up-regulated in three-dimensional cultures relative to two-dimensional controls after 24 hours and persisted throughout the 21 days. CONCLUSIONS: In human processed lipoaspirate cells, the introduction of a three-dimensional scaffold significantly enhances gene markers of angiogenesis and osteogenesis. On three-dimensional scaffolds, processed lipoaspirate cells first up-regulate genes involved with vascular ingrowth and then those involved in bone formation. We believe these differences will significantly impact the design of a bone graft substitute for clinical application.
Subject(s)
Adipocytes/cytology , Neovascularization, Physiologic/genetics , Osteogenesis/genetics , RNA/genetics , Up-Regulation , Adipocytes/metabolism , Alkaline Phosphatase/biosynthesis , Alkaline Phosphatase/genetics , Biomarkers , Collagen Type I/biosynthesis , Collagen Type I/genetics , Humans , Interleukin-8/biosynthesis , Interleukin-8/genetics , Osteocalcin/biosynthesis , Osteocalcin/genetics , Osteonectin/biosynthesis , Osteonectin/genetics , Osteopontin/biosynthesis , Osteopontin/genetics , Reverse Transcriptase Polymerase Chain Reaction , Tissue Scaffolds , Vascular Endothelial Growth Factor A/biosynthesis , Vascular Endothelial Growth Factor A/geneticsABSTRACT
We have characterized a population of mesenchymal progenitor cells from adipose tissue, termed processed lipoaspirate (PLA) cells, which have multilineage potential similar to bone marrow-derived mesenchymal stem cells and are also easily expanded in culture. The primary benefit of using adipose tissue as a source of multilineage progenitor cells is its relative abundance and ease of procurement. We examined the infection of PLA cells with adenoviral, oncoretroviral, and lentiviral vectors. We demonstrate that PLA cells can be transduced with lentiviral vectors at high efficiency. PLA cells maintain transgene expression after differentiation into adipogenic and osteogenic lineages after lentiviral transduction. Therefore, PLA cells and lentiviral vectors may be an efficient combination for use as a therapeutic gene delivery vehicle.
