Amir Elbarbary

Our laboratory has recently characterized a population of cells from adipose tissue, termed processed lipoaspirate (PLA) cells, which have multi-lineage potential similar to bone-marrow-derived mesenchymal stem cells (MSCs). This study is the first comparison of PLA cells and MSCs isolated from the same patient. No significant differences were observed for yield of adherent stromal cells, growth kinetics, cell senescence, multi-lineage differentiation capacity, and gene transduction efficiency. Adipose tissue is an abundant and easily procured source of PLA cells, which have a potential like MSCs for use in tissue-engineering applications and as gene delivery vehicles.

Human processed lipoaspirate (PLA) cells are multipotent stem cells, capable of differentiating into multiple mesenchymal lineages (bone, cartilage, fat, and muscle). To date, differentiation to nonmesodermal fates has not been reported. This study demonstrates that PLA cells can be induced to differentiate into early neural progenitors, which are of an ectodermal origin. Undifferentiated cultures of human PLA cells expressed markers characteristic of neural cells such as neuron-specific enolase (NSE), vimentin, and neuron-specific nuclear protein (NeuN). After 2 weeks of treatment of PLA cells with isobutylmethylxanthine, indomethacin, and insulin, about 20 to 25 percent of the cells differentiated into cells with typical neural morphologic characteristics, accompanied by increased expression of NSE, vimentin, and the nerve-growth factor receptor trk-A. However, induced PLA cells did not express the mature neuronal marker, MAP, or the mature astrocyte marker, GFAP. It was also found that neurally induced PLA cells displayed a delayed-rectifier type K+ current (an early developmental ion channel) concomitantly with morphologic changes and increased expression of neural-specific markers. The authors concluded that human PLA cells might have the potential to differentiate in vitro into cells that represent early progenitors of neurons and/or glia.

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.

Tissue replacement traditionally requires use of autologous tissue and is associated with the attendant morbidity of donor site harvest. In the case of allograft transplantation, there are concerns, similar to those associated with organ transplantation, of rejection and immunosuppression. For these reasons, emphasis has been placed on the development of tissue-engineered substitutes that incorporate autologous stem cells into tissue-engineered scaffolds. The authors' laboratory has characterized a population of cells obtained from processed lipoaspirate (PLA), which have the capacity in vitro to differentiate into osteoblasts, chondrocytes, myocytes, adipocytes, and neuron-like cells. Adipose tissue is an abundant, expendable, and easily obtained tissue that may prove to be an ideal source of autologous stem cells for engineering tissues.