Stem cells derived from a select population of adipose cells obtained by liposuction have been shown in a mouse model to mature into osteogenic cells without the necessity of prior in vitro isolation or differentiation.

Investigators at the University of California, Los Angeles (UCLA; USA) used fluorescence-activated cell sorting (FACS) to select a population of human perivascular stem cells (PSCs) from the stromal vascular fraction (SVF) of adipose tissue obtained by liposuction.

These cells were implanted into mice either without treatment or after exposure to one of the growth factors, BMP2 (bone morphogenetic protein2) or NELL-1 (Nel-like molecule-1, a candidate growth factor able to induce human PSC osteogenesis). Bone-forming capacity was compared to that of traditionally derived SVF stem cells.

Results published in the June 11, 2012, online edition of the journal Stem Cells Translational Medicine revealed that PSCs underwent osteogenic differentiation in vitro and formed bone after intramuscular implantation into mice without the need for predifferentiation. Patient-matched, purified PSCs formed significantly more bone in comparison with traditionally derived SVF by all parameters. Recombinant BMP2 increased in vivo bone formation, but formation of new bone was accompanied by formation of a large mass of fat tissue. In contrast, recombinant NELL-1 selectively enhanced bone formation.

Contributing author Dr. Bruno Péault, professor of orthopedic surgery at UCLA, said, “Human PSCs are plentiful within adipose tissue so that even patients with minimal excess body fat can donate their own fat tissue for harvesting the cells. As an added bonus, the PSCs do not need to be cultured in the laboratory, which cuts down on the time and cost needed to produce them while also reducing the risk of immunogenicity, infection, and genetic instability. The marriage of a competent cell source for growing bones with an efficient growth factor is a logical union for skeletal tissue engineering. We believe our study demonstrates an optimal combination product for local bone formation in patients.”

PSCs are a stem cell-based therapeutic that is readily approvable by the [US] Food and Drug Administration, with potentially increased safety, purity, identity, potency, and efficacy.

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