Understanding Mature Tissue or Organ Stem Cells and Their Clinical Application

Researchers are expanding their understanding of identified adult stem cells, which include blood-forming, brain, skin and skeletal muscle stem cells, while working to isolate stem cells for the lung, liver, kidney, heart and other tissues. This work is providing the basis for ongoing preclinical and clinical trials of organ and tissue regeneration from healthy adult stem cells.

Tissue development and disease

By identifying adult stem cells from other tissues such as lungs or liver, researchers at the institute are working to understand how those tissues develop and what goes wrong when those tissues become diseased. For example, having already identified adult stem cells in the brains of mice and humans, researchers can now use those stem cells to understand how cells of the developing brain differentiate into the many different cell types found in the adult brain. By working out the molecular mechanisms by which adult stem cells self-renew or differentiate, researchers may be able to understand what processes go awry in neurodegenerative diseases such as Alzheimer's disease and Parkinson's disease.

The study of adult stem cells could also lead to insights into cancer cell biology. Recent studies indicate that cancers are continually replenished by a small population of cancer stem cells that are capable of self-renewal. By studying adult stem cells to learn more about the genes involved in self-renewal, it may be possible to identify new molecular targets for drug and immune therapies that destroy the self-renewing cancer stem cells.

Regenerative therapies

Drawing on its increasing understanding of tissue or organ-specific stem cells , the institute is exploring the ability of these cells to replenish or repair damaged or congenitally abnormal tissues or organs. Tissue-specific stem cells may one day be used to replenish cells damaged by Parkinson's disease, Alzheimer's disease, multiple sclerosis or diabetes.

One example of tissue regeneration is in bone marrow transplants, where blood-forming stem cells regenerate the blood of transplant recipients who receive otherwise lethal doses of chemotherapy to destroy all the cancer cells in the body. Stanford was the first institution in the United States to use purified blood-forming stem cells rather than whole bone marrow transplants to regenerate the bone marrow in chemotherapy patients. By using purified stem cells rather than whole bone marrow taken from the patient before chemotherapy, doctors avoid re-injecting patients with their own cancer cells.

Isolating adult stem cells from a variety of tissues in addition to the blood and brain stem cells could also help in other areas of cancer treatment. Doctors could then give high doses of radiation to destroy tumors in tissues such as brain, lungs or liver, and inject tissue-specific stem cells to replace radiation-damaged cells.