Mimicking the functional niche of adipose-derived stem cells for regenerative medicine.

INTRODUCTION: A stem cell (SC) niche is defined as the microenvironment in which the adult SC resides and includes surrounding cells, low oxygen content and growth factor gradients. Crosstalk between SCs and their niche provides signals that keep SCs quiescent, or modulates their activation. AREAS COVERED: This review discusses the characterization of niche conditions in the adipose-derived stem cell (ASC) in vivo environment, and introduces key signalling pathways and autocrine/paracrine regulators of ASCs. EXPERT OPINION: Control of in vivo niche factors (such as low oxygen content, generation of reactive oxygen species and activation of platelet-derived growth factor receptor signalling) should increase ASC yields synergistically and reduce production costs. Additionally, the preconditioning of ASCs with these niche factors prior to transplantation might enhance their regenerative potential. ASC niche is complex, and there are components of the niche that we may not yet understand. Therefore, future research needs to focus on identifying the key regulatory factors of the ASC niche in vivo, and developing a novel method to mimic these niche factors for in vitro manipulation.