Historical mammalian in vitro cell culture is reliant on air oxygen-based culture systems. This is because of the ease of their application and not due to their replication of the physiological milieu. In fact, the in vivo, physiological oxygen (physioxia) levels range from near anoxic to around 14% O2 at the alveoli with a mean range throughout the body’s tissues of 2 – 5% O2. We, and others, have shown previously that maintenance of naïve stemness of both adult blood and embryonic pluripotent stem cells requires a physioxia culture environment.
Respiratory disease and disorder remains an under addressed aspect of research. This is in stark contrast to the exceptional burden it places on healthcare systems. For example, Chronic Obstructive Pulmonary Disease (COPD) is the 3rd leading cause of death and 2nd most common cause of emergency hospital admission in China, has no cure and only progressively ineffective treatment availability. We have now applied the principles of physioxia culture to describe the successful isolation of distal airway stem cells (DASC) from both porcine and human (COPD and healthy) respiratory tissues. These p63+ve DASC are immortal, non-transformed, non-ciliated, ACE2+ve, and retain a capacity to differentiate into all respiratory cell lineages found within the lung. Differentiation was enhanced by exposing physioxia isolated and expanded DASC to air/liquid interfaces while air oxygen isolated DASC rapidly lose their differentiation capacity. In summary, the application of physioxia culture principles to a challenging respiratory model has enabled a bank and lot, reproducible, culture system for enhanced study of respiratory disease and disorder.