Future cell-based therapies such as tissue engineering will benefit from a
source of autologous pluripotent stem cells. For mesodermal tissue engineer
ing, one such source of cells is the bone marrow stroma. The bone marrow co
mpartment contains several cell populations, including mesenchymal stem cel
ls (MSCs) that are capable of differentiating into adipogenic, osteogenic,
chondrogenic, and myogenic cells. However, autologous bone marrow procureme
nt has potential limitations. An alternate source of autologous adult stem
cells that is obtainable in large quantities, under local anesthesia, with
minimal discomfort would be advantageous. In this study, we determined if a
population of stem cells could be isolated from human adipose tissue. Huma
n adipose tissue, obtained by suction-assisted lipectomy (i.e., liposuction
), was processed to obtain a fibroblast-like population of cells or a proce
ssed lipoaspirate (PLA). These PLA cells can be maintained in vitro for ext
ended periods with stable population doubling and low levels of senescence.
Immunofluorescence and flow cytometry show that the majority of PLA cells
are of mesodermal or mesenchymal origin with low levels of contaminating pe
ricytes, endothelial cells, and smooth muscle cells. Finally, PLA cells dif
ferentiate in vitro into adipogenic, chondrogenic, myogenic, and osteogenic
cells in the presence of lineage-specific induction factors. In conclusion
, the data support the hypothesis that a human lipoaspirate contains multip
otent cells and may represent an alternative stem cell source to bone marro
w-derived MSCs.