Adipose-derived stromal cells (ASCs).

Adipose-derived stromal cells (ASCs) are now emerging as a good alternative to bone marrow derived mesenchymal stromal cells (BM-MSC) for cellular therapy. Similarly to BM-MSC, ASCs can be easily isolated as adherent fibroblastoid cell population after processing lipoaspirate samples. Lipoaspiration provides a great number of cells, without extensive manipulation. ASCs express classical mesenchymal markers and only at early passages express CD34. ASCs can differentiate in cells of mesodermal lineages, such as adipocytes, osteocytes and condrocytes. ASCs share with BM-MSC the same ability to inhibit the proliferation of allogeneic, activated immune cells, thus affecting in vivo in animal models the onset and course of rheumatoid arthritis (RA), experimental autoimmune encephalomyelitis (EAE), Crohn's disease (CD), ulcerous colitis (UC) and graft-versus-host disease (GvHD). On the other hand, the main molecular pathway involved in this effect is still unclear. On the basis of this functional property, ASCs are used in different clinical trials to treat RA, CD, UC and GvHD. However, the most promising field of clinical application is represented by bone defect repair. Despite the ability to regenerate injured tissues and to block the progression of inflammatory disorders, some authors reported that ASCs can also induce, in in vivo animal models, the growth and vascularization of solid and hematological tumors. Conversely, ASCs have been shown to hamper tumor cell proliferation, reduce cell viability and induce necrosis. Thus, more accurate studies, collaborative protocols, high standardization of methods, and safety controls are required to exclude transformation of transplanted ASCs.