The importance of culturing primary cells under physiological conditions: proliferation, senescence, pluripotency

Mesenchymal stem cells (MSCs), such as human dental pulp stem cells (hDPSCs), are currently a source for cell therapy. However, cell therapy protocols require 10–400 million cells per treatment, and consequently, they need to be expanded in vitro before implantation, with the inconvenience that MSCs undergo senescence following a certain number of cell expansion passages, loosing their stem cell qualities. Ambient oxygen tension (21% pO2) is normally used for in vitro culture, but physiological levels in vivo range between 3% and 6% pO2. We previously demonstrated that hDPSC proliferation rate is significantly lowered at 21% pO2 due to enhanced oxidative stress, which led to the activation …