Human Embryonic Stem Cells

Stem cells generally are self-renewing primitive cells that can develop into functional, differentiated cells. Human embryonic stem cells (hESCs), which are derived from very early stage embryos called blastocysts, are unique because:

they are pluripotent, which means they can develop into all cells and tissues in the body, and
they self-renew indefinitely in the undifferentiated state because they express high levels of telomerase.

The ability of hESCs to divide indefinitely in the undifferentiated state without losing pluripotency is a unique characteristic that distinguishes them from all other stem cells discovered to date in humans. We have demonstrated that hESCs express telomerase continuously, a characteristic of immortal cells. Other stem cells such as blood or gut stem cells express telomerase at very low levels or only periodically; they therefore age, limiting their use in research or therapeutic applications. hESCs can be expanded in culture indefinitely and hence can be banked for scaled product manufacture.

We intend to use human embryonic stem cell technology to:

enable the development of transplantation therapies by providing standard starting material for the manufacture of cells;
facilitate pharmaceutical research and development practices by providing cells for disease models and screening, and for assigning function to newly discovered genes; and
accelerate research in human developmental biology by identifying the genes that control human growth and development.

Moreover, we have developed scalable processes to differentiate these cells into therapeutically relevant cells. We have developed cryopreserved formulations of hESC-derived cells to enable our business model of delivering "on demand" cells for therapeutic use. We are now testing six different hESC-derived therapeutic cell types in animal models. In four of these cell types we have demonstrated efficacy, as evidenced by durable engraftment or functional improvements of the treated animals. From these studies, we are now advancing development of two hESC-based therapeutics to clinical testing. The most advanced hESC-derived product, GRNOPC1, which contains oligodendroglial progenitor cells, is targeted for the treatment of spinal cord injury. Geron's second hESC product, GRNCM1, is a population of cardiomyocytes, the contractile cells of the heart, which is intended for the treatment of patients with myocardial disease. Geron also has made substantial progress in deriving pancreatic islet β cells for diabetes, osteoblasts for osteoporosis, chondrocytes for osteoarthritis, hepatocytes for liver failure and ADME drug testing, and dendritic cells for two applications, including cancer immunotherapy and graft acceptance (to prevent immune rejection of the other cell types used in therapeutic applications). We own or have licenses to intellectual property covering core inventions and enabling technology in this field.

Geron's hESCs were derived by our collaborators from donated in vitro fertilized blastocysts (very early-stage embryos). We currently have nine hESC lines, seven of which are listed on the NIH stem cell registry; most of our development work so far has focused on three of those lines.

Human Embryonic Stem Cells

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