PureStem® human Embryonic Progenitor Cells (hEPC) overcome significant challenges in regenerative medicine through their purity, their proliferative capacity and their ability to change or “differentiate” into a broad spectrum of cell types in a simplified and controlled fashion. These advantages allow the production, on a commercial scale, of pure cultures of potentially therapeutic cell types that do not contain hazardous “undifferentiated” cell types.


Stem cells are defined by their ability to both continually “proliferate” or make more copies of themselves, and their ability to differentiate into other cell types. They can be grouped into two broad categories; “pluripotent stem cells” such as human Embryonic Stem Cells (hESC) and “adult stem cells” that are found in the tissues of a developed human being. PureStem® hEPC are a special kind of stem cell isolated by BioTime that falls between pluripotent stem cells and adult stem cells and has advantages over both. As can be seen in this illustration of a developmental tree, hESC are the source of all cell types. Adult stem cell occur near the outer branches and the unique hEPC are found at the earliest branching points.

Human pluripotent stem cells exhibit unlimited proliferation and can differentiate into any cell type. However they require complicated differentiation protocols to yield therapeutic cells which are rarely 100% pure thus requiring additional purification steps to remove unwanted cells. PureStem EPC are highly proliferative yet retain the ability to differentiate. The result is an economical source of scalable cultures that can be differentiated to a variety of desirable therapeutic cell types free of contaminating cells.

Adult stem cells, unlike pluripotent stem cells, are limited in their ability to proliferate and are not able to become many cell types needed for therapy. PureStem EPC are highly proliferative relative to adult stem cells and exhibit an ability to produce cell types not attainable using adult stem cells.

BioTime’s PureStem EPC are produced using its proprietary ACTCellerate® cell culture technology with NIH-registered hESC. This technology results in thousands of colonies containing hundreds of types of unique EPC exhibiting purity, robust proliferation and the ability to become unique cell types with therapeutic potential. PureStem EPC have high potential for commercial development as cells for transplantation to treat currently intractable degenerative conditions.