Phenotypic characteristics of feline adipose-derived stem cells affected by cell passage number

In this study we evaluated the influence of passage number on the phenotypic characteristics of feline adipose-derived stem cells (ASCs) in order to develop a broader understanding of their dynamics. Feline ASCs were individually isolated from five domestic cats and subjected to proliferative culture at passage (P) 2, 6 and 10. The cells at each sub-passage were examined in regard to their phenotypic properties associated with multipotent mesenchymal stem cells (MSCs), such as morphology, proliferation kinetics, self-renewal, and expression of MSCs-specific surface markers. The differentiation capacity into adipocytes and osteoblasts was also identified. Feline ASCs appeared with a fibroblast-like morphology with minimal alteration through P10. The rate of cell proliferation gradually decreased, while cell doubling time gradually increased with each passage. A significant decrease in CFU-F efficiency was observed with increasing cell passage number. The ASC population uniformly expressed their characteristic markers CD44 and CD90, but did not express the hematopoietic marker CD45. However, MSC markers gradually decreased in the later passage stages. Feline ASCs were capable of undergoing both adipogenesis and osteogenesis at P2. These findings suggested that the phenotypic characteristics of feline ASCs could be affected by long-term passages, which is potentially very important in regard to their therapeutic application.