Research progress in muscle-derived stem cells Literature retrieval results based on international database

OBJECTIVE： To identify global research trends of muscle-derived stem cells （MDSCs） using a bibliometric analysis of the Web of Science, Research Portfolio Online Reporting Tools of the National Institutes of Health （NIH）, and the Clinical Trials registry database （ClinicalTrials.gov）. DATA RETRIEVAL： We performed a bibliometric analysis of data retrievals for MDSCs from 2002 to 2011 using the Web of Science, NIH, and ClinicalTrials.gov. SELECTION CRITERIA： Inclusion criteria： （1） Web of Science： （a） peer-reviewed articles on MDSCs 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. （c） Year of publication： 2002-2011. （d） Citation databases： Science Citation Index-Expanded （SCI-E）, 1899-present; Conference Proceedings Citation Index-Science （CPCI-S）, 1991-present; Book Citation Index-Science （BKCI-S）, 2005-present. （2） NIH： （a） Projects on MDSCs supported by the NIH. （b） Fiscal year： 1988-present. （3） ClinicalTrials.gov： All clinical trials relating to MDSCs were searched in this database. Exclusion criteria： （1） Web of Science： （a） Articles that required manual searching or telephone access. （b） We excluded documents that were not published in the public domain. （c） We excluded a number of corrected papers from the total number of articles. （d） We excluded articles from the following databases： Social Sciences Citation Index （SSCI）, 1898-present; Arts ＆ Humanities Citation Index （A＆HCI）, 1975-present; Conference Proceedings Citation Index - Social Science ＆ Humanities （CPCI-SSH）, 1991-present; Book Citation Index - Social Sciences ＆ Humanities （BKCI-SSH）, 2005-present; Current Chemical Reactions （CCR-EXPANDED）, 1985-present; Index Chemicus （IC）, 1993-present. （2） NIH： （a） We excluded publications related to MDSCs that were supported by the NIH. （b） We limited the keyword search to studies that included MDSCs within the title or abstract. （3） ClinicalTrials.gov： （a） We excluded clinical trials that were not in the ClinicalTrials.gov database. （b） We excluded clinical trials that dealt with stem cells other than MDSCs in the ClinicalTrials.gov database. MAIN OUTCOME MEASURES： （1） Type of literature; （2） annual publication output; （3） distribution according to journals; （4） distribution according to country; （5） distribution according to institution; （6） top cited authors over the last 10 years; （7） projects financially supported by the NIH; and （8） clinical trials registered. RESULTS： （1） In all, 802 studies on MDSCs appeared in the Web of Science from 2002 to 2011, almost half of which derived from American authors and institutes. The number of studies on MDSCs has gradually increased over the past 10 years. Most papers on MDSCs appeared in journals with a particular focus on cell biology research, such as Experimental Cell Research, Journal of Cell Science, and PLoS One. （2） Eight MDSC research projects have received over US$6 billion in funding from the NIH. The current project led by Dr. Johnny Huard of the University of Pittsburgh-＂Muscle-Based Tissue Engineering to Improve Bone Healing＂-is supported by the NIH. Dr. Huard has been the most productive and top-cited author in the field of gene therapy and adult stem cell research in the Web of Science over last 10 years. （3） On ClinicalTrials.gov, ＂Muscle Derived Cell Therapy for Bladder Exstrophy Epispadias Induced Incontinence＂ Phase 1 is registered and sponsored by Johns Hopkins University and has been led by Dr. John P. Gearhart since November 2009. CONCLUSION： From our analysis of the literature and research trends, we found that MDSCs may offer further benefits in regenerative medicine.