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Umbilical cord matrix (UCM)-derived mesenchymal stem/stromal cells (MSCs) are promising therapeutic candidates for regenerative medicine settings. UCM MSCs have advantages over adult cells as these can be obtained through a non-invasive harvesting procedure and display a higher proliferative capacity. However, the high cell doses required in the clinical setting make large-scale manufacturing of UCM MSCs mandatory. A commercially available human platelet lysate-based culture supplement (UltraGROTM, AventaCell BioMedical) (5%(v/v)) was tested to effectively isolate UCM MSCs and to expand these cells under (1) static conditions, using planar culture systems and (2) stirred culture using plastic microcarriers in a spinner flask. The MSC-like cells were isolated from UCM explant cultures after 11 ± 2 days. After five passages in static culture, UCM MSCs retained their immunophenotype and multilineage differentiation potential. The UCM MSCs cultured under static conditions using UltraGROTM-supplemented medium expanded more rapidly compared with UCM MSCs expanded using a previously established protocol. Importantly, UCM MSCs were successfully expanded under dynamic conditions on plastic microcarriers using UltraGROTM-supplemented medium in spinner flasks. Upon an initial 54% cell adhesion to the beads, UCM MSCs expanded by >13-fold after 5–6 days, maintaining their immunophenotype and multilineage differentiation ability. The present paper reports the establishment of an easily scalable integrated culture platform based on a human platelet lysate supplement for the effective isolation and expansion of UCM MSCs in a xenogeneic-free microcarrier-based system. This platform represents an important advance in obtaining safer and clinically meaningful MSC numbers for clinical translation. Copyright © 2016 John Wiley & Sons, Ltd.

Adipose tissue has emerged as a preferred source of mesenchymal stem/stromal cells (MSC), due to its easy accessibility and high MSC content. The conventional method of isolation of adipose tissue-derived stromal cells (ASC) involves enzymatic digestion and centrifugation, which is a costly and time-consuming process. Mechanical stress during isolation, use of bacterial-derived products and potential contamination with endotoxins and xenoantigens are other disadvantages of this method. In this study, we propose explant culture as a simple and efficient process to isolate ASC from human adipose tissue. This technique can be used to reproducibly isolate ASC from fat tissue obtained by liposuction as well as surgical resection, and yields an enriched ASC population free from contaminating haematopoietic cells. We show that explanting adipose tissue results in a substantially higher yield of ASC at P0 per gram of initial fat tissue processed, as compared to that obtained by enzymatic digestion. We demonstrate that ASC isolated by explant culture are phenotypically and functionally equivalent to those obtained by enzymatic digestion. Further, the explant-derived ASC share the immune privileged status and immunosuppressive properties implicit to MSC, suggesting that they are competent to be tested and applied in allogeneic clinical settings. As explant culture is a simple, inexpensive and gentle method, it may be preferred over the enzymatic technique for obtaining adipose tissue-derived stem/stromal cells for tissue engineering and regenerative medicine, especially in cases of limited starting material.