title: Stem cell therapy in inflammatory bowel disease: which, when and how?
abstract: OBJECTIVE
  Stem cell therapy has emerged as a promising therapeutic strategy for inflammatory bowel diseases (IBDs). Currently, stem cell therapy is not part of the standard of care and is usually only performed as a part of clinical trials. In this review, clinical results, proposed underlying mechanisms, and future research directions will be discussed.
  
  
  RESULTS
  Administration of mesenchymal stem cells (MSCs) and hematopoietic stem cells (HSCs) has been evaluated for IBD treatment over the past years. MSC therapy is being explored as a treatment option for fistulizing Crohn's disease and for luminal Crohn's disease. It is shown to be well tolerated, but results on efficacy are inconsistent. HSC transplantation seems to be very effective, but serious adverse events are common. Therefore, future research should focus on improving efficacy of MSC therapy, and on improvement of safety of HSC therapy.
  
  
  CONCLUSIONS
  Both MSC and HSC therapy offer clinical potential, but currently are not routinely used for IBD treatment. MSC therapy seems well tolerated but results on efficacy are conflicting. HSC transplantation is shown to be effective but safety concerns remain. Nonetheless, for severe refractory IBD cases, stem cell therapy could well become the next-generation treatment option.
authors.affiliation: Department of Digestive Diseases, David Geffen School of Medicine, UCLA, Los Angeles, California 90095, USA. wvandeen@mednet.ucla.edu
authors.forename: Welmoed K
authors.initials: WK
authors.lastname: van Deen
authors.forename: Angelos
authors.initials: A
authors.lastname: Oikonomopoulos
authors.forename: Daniel W
authors.initials: DW
authors.lastname: Hommes
mesh_terms: D018380:Hematopoietic Stem Cell Transplantation / Q000379:methods; D006801:Humans; D015212:Inflammatory Bowel Diseases / Q000209:etiology / Q000276:immunology / Q000628:therapy*; D045164:Mesenchymal Stem Cell Transplantation / Q000379:methods; D033581:Stem Cell Transplantation / Q000379:methods* / Q000639:trends