**Microenvironment of ASCs**

Stem cells are found in a specialized environment, a niche, which controls many aspects of cell behavior - activity, proliferation, and differentiation The microenvironment of the subcutaneous stem cell (niche) refers to a specific location în which the adult subcutaneous cells reside and interact with ASCs and other cells or substrates. The surrounding microenvironment of ASCs provides signals that keep ASCs quiescent or promote either proliferation or differentiation. However, the niche function is to prevent ASC proliferation or differentiation. Several important factors regulate ASCs' characteristics within the niche, including cell–cell and cell-extracellular matrix (ECM) relationships, growth factors, oxygen tension, and cytokine signals [11].
