Clinical efficacy and safety of stem cells in refractory Crohn's disease: A systematic review

BackgroundRefractory Crohn's disease, especially when complicated by complex perianal fistula, seriously reduces the patients' quality of life. Preclinical and clinical studies indicate stem cells may be a promising therapy for refractory Crohn's disease.ObjectiveTo systematically review evidence on clinical efficacy and safety of stem cells in refractory Crohn's disease.MethodsA detailed search was performed to identify randomized controlled trials (RCT), systematic reviews of RCTs or high-quality non-RCTs published before September 2015 in the Cochrane Library, PubMed, Medline, EMBASE, and the ISI Web of Knowledge databases. Search terms included: MSC (mesenchymal stem cell), stem cells, HSC (hematopoietic stem cell), IBD (inflammatory bowel disease), CD (Crohn's disease), UC (ulcerative colitis). Two authors independently extracted data for analysis using predefined selection criteria and quality indicators. Trials were also retrieved from the website of www.Clinicaltrials.gov.Results18 of the 225 articles identified met the inclusion criteria. However, there were only two studies that had control groups. Therefore, a brief qualitative analysis of the evidence was considered to be more adequate. It seems stem cells can reduce Crohn's Disease Activity Index (CDAI) and help alleviate CD symptoms. Moreover, the incidence of serious adverse events caused by stem cell transplantation was very low (1.75%, 7/400).ConclusionsStem cell therapy for CD is very promising, but large, multicenter and randomized clinical trials are needed to further support their therapeutic benefits.