10/12/02
Brie Zeltner
Plain Dealer Reporter

Researchers at University Hospitals of Cleveland are getting closer to being able to use stem cells acquired from umbilical cord blood to regenerate blood vessels in damaged heart muscle.

Their research is being bolstered by a $450,000 grant from the National Institutes of Health to continue preclinical trials in mice. The study will test the efficacy of injecting cord blood stem cells into damaged cardiac muscle to develop new blood vessels, says Dr. Vincent Pompili, the study's principal investigator and director of Interventional Cardiology at UH.

Stem cell research offers enormous promise for treating a wide variety of diseases by regenerating damaged tissues, vessels and even organs. After initial research in 1998 established that stem cells taken from human embryos could be cultured and grown into specialized tissues, the possible medical applications of the technique seemed endless.

The use of aborted human embryos to supply the stem cells for this research, however, has posed serious ethical questions for both researchers and lawmakers, and provoked President Bush to limit federal funding for research to a few existing embryonic cell lines. The small supply has frustrated the efforts of scientists to develop these potentially life-saving techniques.

Umbilical cord blood samples provide an excellent alternative source of stem cells because they are collected after the deliveries of healthy infants, on a voluntary basis.

There are numerous advantages to using cord blood samples to collect stem cells for research, says Dr. Mary Laughlin, director of Allogenic Bone Marrow Transplantation at UH and co-investigator for the study. Beyond ethical concerns, cord blood samples are pathogen-free and, unlike bone marrow samples, are available from every ethnic group for tissue matching, she says. And with millions of healthy babies born each year, there is a potentially large supply that can be stored and available on short notice.

With parental permission, a 4- to 6-ounce sample of cord blood can be obtained from the umbilical cord and placenta, material that would normally be discarded after delivery. The sample is shipped and stored at one of three public banks or, for a fee, can be stored by two private companies for use by family members only.

Researchers are then able to isolate stem cells from the cord blood that have the advantage of being immunologically "immature," meaning that they lack the defense systems of adult stem cells, and are therefore more easily accepted by a wide variety of patients.

Laughlin has been using cord blood stem cells for the past nine years to treat rare blood disorders such as leukemia, lymphoma and myeloma.

Cord blood stem cells have a proven track record for treating humans, while embryonic stem cells have not yet been used in people.

There is some concern that embryonic cells, because they are "primitive," could become cancerous when injected into human beings. There is evidence from Laughlin's work and other studies in leukemia patients that this is not happening with cord blood.

The application to cardiac patients, called "therapeutic angiogenesis" is new, says Pompili. The procedure will benefit those lacking sufficient blood flow to the heart muscle due to artery blockage by regrowing blood vessels to supply the affected area. In particular, the patients involved in the trial will be those who are not candidates for the traditional surgical interventions - balloon angioplasty and bypass surgery, he says.

Nearly 5 million Americans live with heart failure today, and there are about 550,000 cases diagnosed each year, according to the American Heart Association. With preclinical trials in mice showing positive results, Pompili and Laughlin hope to begin initial clinical trials in human patients in the next 18 months.

To reach this Plain Dealer reporter:

bzeltner@plaind.com, 216-999-5703