Genetic markers of osteogenesis and angiogenesis are altered in processed lipoaspirate cells when cultured on three-dimensional scaffolds.
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.
Huang
Catherine K
CK
Los Angeles, Calif. From the Plastic Surgery Research Laboratory, Veterans Affairs Greater Los Angeles Healthcare System, and the Department of Head and Neck Surgery and Division of Plastic and Reconstructive Surgery, University of California, Los Angeles.
Huang
Weibiao
W
Zuk
Pat
P
Jarrahy
Reza
R
Rudkin
George H
GH
Ishida
Kenji
K
Yamaguchi
Dean T
DT
Miller
Timothy A
TA
D017667:Adipocytes / Q000166:cytology* / Q000378:metabolism; D000469:Alkaline Phosphatase / Q000096:biosynthesis / Q000235:genetics; D015415:Biomarkers; D024042:Collagen Type I / Q000096:biosynthesis / Q000235:genetics; D006801:Humans; D016209:Interleukin-8 / Q000096:biosynthesis / Q000235:genetics; D018919:Neovascularization, Physiologic / Q000235:genetics*; D015675:Osteocalcin / Q000096:biosynthesis / Q000235:genetics; D010012:Osteogenesis / Q000235:genetics*; D015676:Osteonectin / Q000096:biosynthesis / Q000235:genetics; D053495:Osteopontin / Q000096:biosynthesis / Q000235:genetics; D012313:RNA / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D054457:Tissue Scaffolds; D015854:Up-Regulation; D042461:Vascular Endothelial Growth Factor A / Q000096:biosynthesis / Q000235:genetics
D015415:Biomarkers; D024042:Collagen Type I; D016209:Interleukin-8; D015676:Osteonectin; D042461:Vascular Endothelial Growth Factor A; D015675:Osteocalcin; D053495:Osteopontin; D012313:RNA; D000469:Alkaline Phosphatase