Table 1.

Documented Causes of Mesenchymal Stem Cell Senescence

in vitro	Reference	in vivo	Reference
High O2 tension in culture	29	SASP	87, 61
DNA methylation variation	55	PROGERIA	59, 63, 121
Cytokines, growth factors	71, 115	Exosomes	58, 102
SASP	47, 96–122
Noncoding RNA	20, 14–34
Exosomes	114
ROS	46, 105

ROS, reactive oxygen species; SASP, senescence-associated secretory phenotype.