Adult Telomerase Positive Stem Cells: Isolation, Plating and Propagation

The adult human body is composed of trillions and trillions of cells. These cells can be divided into three categories: functional [differentiated] cells comprising 40%, maintenance [progenitor] cells comprising 59%, and healing [stem] cells comprising 1% of the cells of the body. Healing stem cells were discovered in 1975 residing within the connective tissue stroma of adult terrestrial salamanders undergoing complete limb regeneration. They were shown to form all damaged or lost tissues of an amputated limb, thereby restoring function to the limb. Since 1975, these cells have been extensively characterized. The healing stem cells are uniquely different from functional cells and maintenance cells. Healing cells are telomerase positive which gives them an essentially unlimited proliferation potential. There are 8 distinct subcategories of healing stem cells based on multiple parameters, including differentiation potentials. In vivo, they do not synthesize and secrete their own substratum, and therefore one must be provided for them. They can form multiple cell layers in vitro. In situ, they reside in connective tissue niches interspersed throughout the body as dormant, hibernating, quiescent cells. They can be stimulated to proliferate and mobilize into the blood stream as non-activated cells, but they need to be activated to function to replace damaged cells and tissues. Activation occurs by unmasking homing receptors on their cell surfaces and unmasking cell surface receptors for exosomes containing biological agents. Due to their uniqueness, special methodologies were developed for their isolation, plating, and propagation. This report describes those methodologies in detail.