OBJECTIVETo investigate the dedifferentiation of mature adipocytes and the possibility of adipose tissue engineering using dedifferentiated adipocytes.

METHODSHuman adipose tissue was harvested from healthy women undergoing abdominal liposuction procedures, and mature adipocytes were isolated with enzymatic digestion and cultured by ceiling adherent culture method, using the third-passage cells for subsequent experiment. The cells were cultured in adipogenic, chondrogenic or osteogenic media, and Oil red-O staining, Alcian blue staining and Alizarin red staining were used for dedifferentiation identification. The third-passage cells labeled with DiI were mixed with fibrin glue and injected subcutaneously on one side of the nude mouse back (n=6), and fibrin glue solution without cells as control was injected on the other side (n=6). After 8 weeks of cell implantation, the specimens were harvested for general observation and histological, Oil red-O staining and fluorescent microscope analyses.

RESULTSMature adipocytes were round, unilocular cells. After ceiling adherent culture, the adipocytes underwent morphological changes into fibroblast-like cells indicating their dedifferentiation. The dedifferentiated adipocytes were induced for adipogenic, chondrogenic and osteogenic differentiation in specified media. Eight weeks after the cell injection in nude mice, newly formed tissue occurred which was identified as mature adipose tissue. The implants without cells were completely absorbed in the control group.

CONCLUSIONMature adipocytes can dedifferentiate in vitro culture, and the dedifferentiated adipocytes are capable of differentiating into adipogenic, chondrogenic and osteogenic lineages. Adipose tissue engineering can be achieved in vivo using the dedifferentiated adipocytes as the seed cells.