Molecular mechanism of extrinsic factors affecting anti-aging of stem cells

Figure 1 Stem cell maintenance and altered state during aging. A: Secreted growth factors, paracrine, calorie restriction, hypoxic micro-environment, ECM, and niche cells maintain stem cell functions. Quiescent, self-renewing, and multipotent status of stem cell are further maintained through intracellular hypoxia-responsive element, epigenetic and genomic regulators, and mitochondria; B: However, the status of stem cell is altered with decreased niche cells, fragmented ECM, increased genomic and mitochondria DNA damage, and increased ROS during aging. ECM: Extracellular matrix; ROS: Reactive oxygen species; SC: Stem cell.