[The in vitro study of the human adipose tissue-derived stromal cells differentiating into the neuron-like cells]

To investigate the possibility of the adipose tissue derived stromal cells (ADSCs) to differentiate into the neuron-like cells and to explore a new cell source for the transplantation related to the central nervous system.

Adipose was digested by collagenase, cultured in the fetal bovine serum containing a medium. Trypse was used to digest the cells and the cell passage was performed. The 3rd to the 9th passage ADSCs were used to make an induction. Isobutyl-methylxanthine, indomethacin, insulin, and dexamethasone were used to induce the ADSCs to differentiate into the neuronlike cells and adipocytes. Sudan black B and immunocytochemistry were used to identify the cells.

A population of the ADSCs could be isolated from the adult human adipose tissue, they were processed to obtain a fibroblast-like population of the cells and could be maintained in vitro for an extended period with the stable population doubling, and they were expanded as the undifferentiated cells in culture for more than 20 passages, which indicated their proliferative capacity. They expressed vimentin and nestin, and characteristics of the neuron precursor stem cells at an early stage of differentiation. And the majority of the ADSCs also expressed the neuron-specific enolase and beta III-tubulin, characteristics of the neurons. Isobutyl-methylxanthine, indomethacin, insulin, and dexamethasone induced 40%-50% of ADSCs to differentiate into adipocytes and 0. 1%-0.2% of ADSCs into neuron-like cells. The neuron-like cells had a complicated morphology of the neurons, and they exhibited a neuron phenotype, expressed nestin, vimentin, neuron-specific enolase and beta III-tubulin, but some neuron-like cells also expressed the smooth muscle actin (SMA), and the characteristics of the smooth muscle cells; however, the neurons from the central nervous system were never reported to express this kind of protein. Therefore, the neuron-like cells from the ADSCs could be regarded as functional neurons.

Our results support the hypothesis that the adult adipose tissue contains the stem cells capable of differentiating into the neuron-like cells, and they can overcome their mesenchymal commitment, which represents an alternative autologous stem cell source for transplantation related to the central nervous system.