Human embryonic stem cell lines and their use in international research

Abstract

Research in human pluripotent stem cells, including human embryonic stem cells (hESC) and human induced pluripotent stem cells (hiPSC), is one of the most dynamic research fields. Despite the high public attention, especially for hESC research, there is only scattered information on the number of hESC lines and the degree, dynamics, and diversification of their use on a global level. In this study we present data on the current number of publicly disclosed hESC lines, on the extent and impact of experimental work involving hESCs, and on the use of specific hESC lines in international research. The results are based on the evaluation of nearly 1,000 research papers published by the end of 2008, which describe experimental work on hESCs, and of a comprehensive database of published hESC lines. The average impact of hESC research papers is high at 7.422, with a predominance of research output by the United States. Of at least 1,071 original hESC lines derived up to November 2009 at 87 institutions in 24 countries, only a fraction is thoroughly characterized. Our data show the global predominance of a few hESC lines in research, but also reveal remarkable country-specific differences. Comparison of hESC and hiPSC application did not show a diminished role for hESC research, but rather revealed that, up to this time, both fields continue to expand, exist independently, and partially overlap.

Figure 1

Share of published hESC research from selected countries in the total number of research papers published 2003–2008 worldwide in English language journals.

Figure 2

Use of hESC lines of selected providers in international research and in published research from selected countries. A: The share of cell lines from a specific provider in the cell lines used overall in hESC research papers published 1998–2008. BresaGen, BresaGen, Inc., Athens, Georgia; Cellartis, Cellartis AB, Göteburg, Sweden; ESI, ES Cell International Pte Ltd, Singapore; HSCI, Harvard Stem Cell Institute, Massachusetts; Technion, Israel Institute of Technology, Haifa, Israel; UCSF, University of California San Francisco, California; WiCell, WiCell Research Institute, Madison, Wisconsin. Cell lines from other providers contain hESC lines from 48 providers such as Karolinska Institute, Stockholm, Sweden (3.4%); Seoul National University, Seoul, Korea (3.0%); Kyoto University, Japan (2.4%); University of Newcastle, United Kingdom (1.8%); and University of Sheffield, United Kingdom (1.3%). Note that in many studies more than one hESC line was used. B: The percentage of hESC papers from a specific country produced with cell lines of the given providers. Cell lines from providers other than those specifically named were grouped in “other providers.”