Human subcutaneous adipose tissue subjected to cold shock as source of viable cell population with characteristics of multipotent mesenchymal stromal cells

A cell population with characteristics of multipotent mesenchymal stromal cells (MMSCs) was isolated from human subcutaneous adipose tissue (SAT) submitted to a deep freezing (at −70°C) without cryoprotector. Under critical conditions for tissue, the cells retained their viability in vitro and were adhesive to plastic. The cell population was characterized by homogeneity and was represented by small cells (7 μm in diameter) with fibroblast-like morphology. The cytofluorimetric analysis of the cells revealed the presence of antigens on their surface whose expression is characteristic of MMSCs, including CD29, CD44, CD49a,b,d, CD73, CD90, CD105, CD166, and HLA ABC. The cells were negative for CD34, CD45, which are markers of hematopoietic cells; CD31, a marker of endothelial cells; and Stro-1, as well as antigens of the major histocompatibility complex of the II class HLA DR, DP, and DQ. On average, the proportion of cells that carry the receptor of the stem-cell factor c-kit (CD117) amounted to 3%. Upon induction to differentiation in vitro, these cells turned out to be able to form cells similar to cells of bone, adipose, and cartilage tissues. Karyological analysis (GTG staining method) demonstrated the diploid set of chromosomes of cells, without aneuploidy and structural reconstruction of chromosomes. Thus, it has been established that, in SAT submitted to low-temperature shock, a viable population of cells with a phenotype similar MMSCs is preserved.