BioWorld International Correspondent

LONDON - An Anglo-American collaboration claimed it has developed the first reproducible method for extracting and culturing "embryonic-like" stem cells from umbilical cord blood. The cells subsequently were induced to differentiate into hepatocytes, demonstrating they are an ethical and reliable alternative to embryonic stem cells and have similar therapeutic potential, said researchers from Kingston University School of Life Sciences in London and the University of Texas Medical Branch in Galveston.

Colin McGuckin, of Kingston University, said the cord blood-derived embryonic-like stem cells (CBEs), combine the potential therapeutic range of embryonic stem cells with the ethical acceptability of adult stem cells derived from blood or bone marrow. "We have found a unique group of cells that bring together the essential qualities of both types of stem cells for the first time."

The CBEs were isolated by sequential immunomagnetic removal of the other blood components, and then cultured for at least 20 weeks. The resultant CBEs were positive for five accepted markers of embryonic stem cells.

They subsequently were cultured in a microgravity bioreactor with a hepatocyte growth medium. After four weeks, the cells expressed the characteristic hepatic markers, cytokeratin-18, alpha fetoprotein and albumin.

Umbilical cord blood represents an ample source of stem cells with the added advantage of na ve immune status and relatively long telomeres.

"Acquiring stem cells from embryos has major limitations because it is difficult to obtain enough cells to transplant as well as getting the right tissue type for the patient," McGuckin said. "Using cord blood overcomes that obstacle because we can produce more stem cells, and with a global birth rate of 100 million babies a year, there is a better chance of getting the right tissue type for the many patients out there waiting for stem cell therapy."

One of the U.S. researchers, Randall Urban, director of the University of Texas Stark Diabetes Center, said the next stage of the collaboration aims to produce islet cells.

"We plan to use this technology to engineer pancreatic tissue as we work toward our goal of developing a cure for Type I diabetes," he said.

The UK arm of the collaboration is funded as part of the Department of Trade and Industry's program to promote the commercialization of stem cell research.

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