Researchers in the U.S. say they may have found a new and better source for harvesting stem cells: the placentas that are often discarded after birth.

The research from Children's Hospital & Research Center Oakland found there are far more stem cells in placentas than in umbilical cord blood, the traditional source for stem cells, and they can be safely extracted for transplantation.

"Yes, the stem cells are there; yes, they are viable; and yes, we can get them out," declared Dr. Frans Kuypers, one of the scientists who led the research with fellow scientist Vladimir Serikov.

The study was conducted using placentas from healthy women undergoing elective Caesarean section. It will be the feature story in the July 2009 issue of Experimental Biology and Medicine.

The scientists said it is highly likely the cells could be used in therapies to cure chronic blood-related disorders such as sickle cell disease, thalassemia, and leukemia.

One of the limits of umbilical cord blood is that the stem cells it contains are few in number. That makes the likelihood that they can be used to cure a blood disorder in adults fairly slim. Researchers hope that stem cells from the placenta will provide a bigger supply.

Kuypers explained that even when a patient receives a cord blood transplant, there may not be enough stem cells in the umbilical cord to successfully treat their disorder.

"The greater supply of stem cells in placentas will likely increase the chance that an HLA (human leukocyte antigen) matched unit of stem cells engrafts, making stem cell transplants available to more people. The more stem cells, the bigger the chance of success," said Kuypers.

Kuypers and Serikov have developed a patent-pending method that will allow the freezing of placentas to store them in a way that allows them to later be defrosted and to enable the extraction of viable stem cells. The method will make it possible for companies to gather, ship and store placentas in a central location.

"We're looking for a partnership with industry to get placenta-derived stem cells in large quantities to the clinic," said Kuypers in a statement.

He added that while more research is needed to explore the maximum potential of this latest discovery, he is optimistic his work will lead to cures.

"Someday, we will be able to save a lot more kids and adults from these horrific blood disorders."