Effects of Adipose-Derived Stem Cell Extract on Peripheral Nerve Cells

Adipose-derived stem cells (ADSCs) can be obtained from adipose tissue, which is considered clinically dispensable. ADSCs have the ability to differentiate not only into adipocytes and osteoblasts but also into various other cell types, such as nerve cells and cardiomyocytes. However, the clinical application of ADSCs in stem cell therapy is hampered by the risk of transplant rejection and the need for facilities for their storage and transportation. In comparison, cell extracts (CEs) obtained from stem cells by freeze-thawing and lysis are less tumorigenic and immunogenic. However, there are currently no studies on the application of ADSC-derived CEs (ADSC-CEs) in peripheral nerve regeneration. Therefore, in this study, we investigated the effects of ADSC-CEs on proliferation and neurite extension in peripheral nerve cells. ADSCs were harvested from the inguinal region of mice, and ADSC-CEs were obtained following repeated freeze-thawing of ADSCs. We examined the effects of the ADSC-CEs, added to the culture medium, on glial fibrillary acidic protein (GFAP) expression and proliferation in Schwann cells. Moreover, we examined the effects of the ADSC-CEs on neurite length in DRG neurons and PC12D cells. ADSC-CEs stimulated the proliferation of Schwann cells, elevated GFAP expression in these cells, and promoted the elongation of DRG neuron and PC12D cell projections. Notably, heat treatment of the ADSC-CEs abolished these effects. Together, these findings suggest that ADSC-CEs may have therapeutic application in peripheral nerve regeneration.