Influence of the mesenchymal stromal cell source on the hematopoietic supportive capacity of umbilical cord blood-derived CD34+-enriched cells

• Published in: Stem cell research & therapy 2021-07, Vol.12 (1), p.1-399, Article 399
• Main Authors: Bucar, Sara, Branco, André Dargen de Matos, Mata, Márcia F, Milhano, João Coutinho, Caramalho, Ãris, Cabral, Joaquim M. S, Fernandes-Platzgummer, Ana, da Silva, Cláudia L
• Format: Article
• Language: English
• Subjects: Adipose tissue; Adipose tissues; Blood platelets; Bone marrow; CD34 antigen; CD7 antigen; CD90 antigen; Cell culture; Cell number; Cord blood; Cryopreservation; Fetal calf serum; Fibrin; Fibrinogen; Fibroblast growth factor 2; Glucose; Growth factors; Hematopoietic stem cells; Human hematopoietic stem/progenitor cells; Leukocytes (mononuclear); Lymphocytes T; Mesenchymal stem cells; Mesenchymal stromal cells; Mesenchyme; Neutrophils; Progenitor cells; Serum-free medium; Stem cells; Stromal cells; T cells; Transplants & implants; Umbilical cord; Umbilical cord blood; Umbilical cord matrix; Xenografts
• ISSN: 1757-6512; 1757-6512
• DOI: 10.1186/s13287-021-02474-8

Background Umbilical cord blood (UCB) is a clinically relevant alternative source of hematopoietic stem/progenitor cells (HSPC). To overcome the low cell number per UCB unit, ex vivo expansion of UCB HSPC in co-culture with mesenchymal stromal cells (MSC) has been established. Bone marrow (BM)-derived MSC have been the standard choice, but the use of MSC from alternative sources, less invasive and discardable, could ease clinical translation of an expanded CD34.sup.+ cell product. Here, we compare the capacity of BM-, umbilical cord matrix (UCM)-, and adipose tissue (AT)-derived MSC, expanded with/without xenogeneic components, to expand/maintain UCB CD34.sup.+-enriched cells ex vivo. Methods UCB CD34.sup.+-enriched cells were isolated from cryopreserved mononuclear cells and cultured for 7 days over an established feeder layer (FL) of BM-, UCM-, or AT-derived MSC, previously expanded using fetal bovine serum (FBS) or fibrinogen-depleted human platelet lysate (HPL) supplemented medium. UCB cells were cultured in serum-free medium supplemented with SCF/TPO/FLT3-L/bFGF. Fold increase in total nucleated cells (TNC) as well as immunophenotype and clonogenic potential (cobblestone area-forming cells and colony-forming unit assays) of the expanded hematopoietic cells were assessed. Results MSC from all sources effectively supported UCB HSPC expansion/maintenance ex vivo, with expansion factors (in TNC) superior to 50x, 70x, and 80x in UCM-, BM-, and AT-derived MSC co-cultures, respectively. Specifically, AT-derived MSC co-culture resulted in expanded cells with similar phenotypic profile compared to BM-derived MSC, but resulting in higher total cell numbers. Importantly, a subpopulation of more primitive cells (CD34.sup.+CD90.sup.+) was maintained in all co-cultures. In addition, the presence of a MSC FL was essential to maintain and expand a subpopulation of progenitor T cells (CD34.sup.+CD7.sup.+). The use of HPL to expand MSC prior to co-culture establishment did not influence the expansion potential of UCB cells. Conclusions AT represents a promising alternative to BM as a source of MSC for co-culture protocols to expand/maintain HSPC ex vivo. On the other hand, UCM-derived MSC demonstrated inferior hematopoietic supportive capacity compared to MSC from adult tissues. Despite HPL being considered an alternative to FBS for clinical-scale manufacturing of MSC, further studies are needed to determine its impact on the hematopoietic supportive capacity of these