Stem cell transplantation for treating spinal cord injury A literature comparison between studies of stem cells obtained from various sources

OBJECTIVE： To identify global research trends of stem cell transplantation for treating spinal cord injury using a bibliometric analysis of the Web of Science. DATA RETRIEVAL： We performed a bibliometric analysis of data retrievals for stem cell transplantation for treating spinal cord injury from 2002 to 2011 using the Web of Science. SELECTION CRITERIA： Inclusion criteria： （a） peer-reviewed articles on stem cell transplantation for treating spinal cord injury that were published and indexed in the Web of Science; （b） type of articles： original research articles, reviews, meeting abstracts, proceedings papers, book chapters, editorial material, and news items; and （c） year of publication： 2002-2011. Exclusion criteria： （a） articles that required manual searching or telephone access; （b） documents that were not published in the public domain; and （c） a number of corrected papers from the total number of articles. MAIN OUTCOME MEASURES： （1） Annual publication output; （2） distribution according to country; （3） distribution according to institution; （4） distribution according to journals; （5） distribution according to funding agencies; and （6） top cited articles over the last 10 years. RESULTS： Bone marrow mesenchymal stem cells and embryonic stem cells have been widely used for treating spinal cord injury. In total, 191 studies of bone marrow mesenchymal stem cell transplantation and 236 studies of embryonic stem cell transplantation for treating spinal cord injury appeared in the Web of Science from 2002 to 2011, and almost half of which were derived from American or Japanese authors and institutes. The number of studies of stem cell transplantation for treating spinal cord injury has gradually increased over the past 10 years. Most papers on stem cell transplantation for treating spinal cord injury appeared in journals with a particular focus on stem cell research, such as Stem Cells and Cell Transplantation. Although umbilical cord blood stem cells and adipose-derived stem cells have been studied for treating spinal cord injury, the number of published papers was much smaller, with only 21 and 17 records, respectively, in the Web of Science. CONCLUSION： Based on our analysis of the literature and research trends, we found that stem cells transplantation obtained from various sources have been studied for treating spinal cord injury; however, it is difficult for researchers to reach a consensus on this theme.