Using umbilical cord blood for regenerative therapy: Proof or promise?

The identification of nonhematopoietic progenitor cells in cord blood has spawned great interest in using cord blood cells for new indications in regenerative therapy. Many preclinical studies demonstrated improvement in reperfusion and markers of organ recovery using cord blood‐derived cells in a range of animal models. Initial results heralded increasing clinical interest regarding the use of cord blood for regenerative therapy. Initial clinical studies were largely uncontrolled feasibility studies that were case series and reported on small numbers of patients. The emergence of controlled studies has been slower, although multiple controlled studies have been conducted in patients with cerebral palsy and type I diabetes. Heterogeneity in the cellular product, patients, study design, and the timing of outcome measurements remains barriers to meta‐analysis and a clearer understanding of efficacy. Controlled studies of modest size have been reported for a range of additional conditions. The conduct of controlled clinical trials to evaluate potential new uses of cord blood for regenerative therapy remains essential. None of the indications studied to date can be regarded as proven. Moreover, consistency in outcome reporting in terms of the instruments used and the time points for assessment after therapy are needed, including longer follow‐up of study participants. Frequent and careful evaluation of the evidence will allow cord blood banks, health care providers, and patients to assess potential new options in the use of cord blood for regenerative therapy. Description of cell types derived from umbilical cord blood and their progression along the pathway to maturity in clinical studies (to the best of our knowledge). Abbreviations: ECFC, endothelial colony‐forming cells; MSC, mesenchymal stromal cells; USSC, unrestricted somatic stromal cells. Abbreviations: ECFC, endothelial colony‐forming cells; MSC, mesenchymal stromal cells; USSC, unrestricted somatic stromal cells.