(HealthDay News) – A population of stem cells isolated from adipose tissue can differentiate into bone more easily and efficiently than other fat cell populations.
To avoid the unreliable bone formation caused by the heterogeneity of the stromal vascular fraction of adipose tissue previously used for bone production, Aaron W. James, MD, from the University of California in Los Angeles, and colleagues used fluorescence-activated cell sorting to purify human perivascular stem cells (hPSCs) from adipose tissue on the basis of cell surface markers.
The researchers found that hPSCs differentiated into bone in vitro within days after incubation in osteogenic medium and in vivo within six weeks after being placed on a collagen sponge and inserted intramuscularly into immunodeficient mice, without the need for predifferentiation. For producing bone, hPSCs were more effective than stromal vascular cells. When added to hPSCs for intramuscular implants, the growth factor Nel-like molecule 1 (NELL-1) selectively enhanced bone formation, while recombinant bone morphogenetic protein 2 increased bone formation with an adipogenic response.
“Through a series of in vivo experiments, we have optimized a combination product for local bone formation by delivering autologous, purified adult hPSCs and an osteoinductive protein (NELL-1) on an acellular allograft bone scaffold,” the authors write. “Further studies will extend our findings and apply the robust osteogenic potential of hPSCs to the healing of bone defects.”
Several authors have patents related to PSCs and NELL-1, several are founders of Bone Biologics Inc., and several disclosed financial ties to Scarless Laboratories Inc.