An international consortium of scientists, led in part by a USC researcher, recently published the largest existing survey comparing genetic and chemical traits of human embryonic stem cell lines from around the world.

“You could call this an encyclopedia of embryonic stem cells,” said Martin Pera, director of the Center for Stem Cell and Regenerative Medicine at the Keck School of Medicine and member of the International Stem Cell Initiative (ISCI) steering committee.

The study, which appears in the July 2007 issue of Nature Biotechnology and is available online, compared 59 lines of stem cells from 17 laboratories around the world and assessed the similarities and differences in the expression of many common molecular markers.

Researchers also identified certain cell surface antigens and developmentally regulated genes that characterize all human embryonic stem cell lines isolated to date, despite the cell lines’ variety of genetic backgrounds and growth conditions. The similarities identified in the study will help set benchmarks for future stem cell work, Pera said.

The next phase of the initiative will be to assess the various forms of culture media upon which stem cells are grown, as well as address the genetic stability of stem cell lines, Pera said. The huge scope of research the ISCI addresses necessitates the large-scale international collaboration between stem cell research entities, he says.

The study will be an excellent springboard for future stem cell characterization and research, leaders of the ISCI said.

The ISCI is a working group of the International Stem Cell Forum, which aims to encourage collaboration and support in the development of new stem cell applications as well as promote good research practices. U.S. research entities, including the California Institute for Regenerative Medicine and the National Institutes of Health, are heavily involved in the forum.

“Work on this scale would not have been possible without a large, coordinated international effort,” Pera said. “More laboratories are joining the ISCI even now for the next phase of its work. It is unique in the embryonic stem cell field in terms of international collaborative studies—there is nothing like the ISCI.”

Pera said an overarching goal of the forum and the initiative is to spark more large-scale collaboration and cooperation in the hunt for stem cell knowledge and its potentially lifesaving applications.

“I hope that the ISCI will create a precedent for future international collaborations in stem cell research,” Pera said.

“The role for such effort lies in addressing questions where data from large numbers of stem cell lines from many different laboratories are required to reach overarching conclusions about the properties of stem cells or the techniques used to study them,” he added.

Peter W. Andrews, Nissim Benvenisty, Barbara B. Knowles, Ronald D. G., Martin F. Pera, Janet Rossant, Henrik Semb, Glyn N. Stacey, Steve K. W. Oh, “Characteristics of Human Embryonic Stem Cell Lines: Results from the International Stem Cell Initiative.” Nature Biotechnology, July 2007: Vol. 25, No. 7 (803-816).