Stem Cell Therapy :: New treatment option – stem cells

In principle, stem cells (immature cells that have not yet differentiated into specific types of cells) can be used to repair bone, cartilage, tendon and other injured or aged tissues. These cells can be derived from the patient’s own bone marrow and thus present no problem of immune rejection.

Biologist at Osiris Therapeutics, in Baltimore, MD, have shown that human mesenchymal stem cells can be converted into bone cells, cartilage cells, fat cells and the stroma cells in the bone marrow that provide support for blood-forming cells.

Dr. Daniel R. Marshak, Osiris’ chief scientific officer, said the mesenchymal stem cells could be formulated so that, when inserted in the right place in the body, they would change into the appropriate tissue.

Tests in animals show that when the cells are grown on ceramic and put into bone, they turn into bone-forming cells. If grown in a gel and inserted into cartilage, they metamorphose into cartilage cells. If injected into the bloodstream, the cells take up residence in the bone and turn into stroma cells.

A clinical trial is under way with breast cancer patients to explore the cells’ stroma-forming abilities. Lack of stroma to support blood-forming cells may be why the bone marrow transplants given to cancer patients after chemotherapy are not always successful.

With Novartis AG, the Swiss pharmaceutical company, Osiris also plans to test in humans the cells’ abilities to form new bone, tendon and cartilage.

The cells can also be converted to fat cells, which could prove useful in cosmetic surgery and possibly as material for breast implants.

Dr. Mark F. Pittenger,who identified the various factors needed to convert the cells into bone, cartilage, and fat, said he is now working to change them into heart-muscle cells. People are born with a fixed number of heart-muscle cells and the heart grows by enlargement of these cells, not by growing more. “We hope at the least we could prevent some of the scarring after a heart attack by implanting new cells,” Pittenger said.

The human mesenchymal stem cells found in adult bone marrow are derived from the mesoderm, one of the three tissue types of the early embryo and the source of all the body’s bone and connective tissue. The adult stem cells evidently retain much, and possibly all, of the mesoderm’s magical plasticity.


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