Human Mesenchymal Stromal Cells from Bone Marrow and Neonatal Sources: A Comparative In Vitro Study of Their...

Background/Objectives: Mesenchymal stromal cells (MSCs) isolated from neonatal sources have been proposed in clinical cell therapy to enhance hematopoietic stem cell transplantation due to their hematopoietic support capacity. Here we evaluated this capacity, particularly the lymphopoietic potential that remains poorly understood. Methods: In this in vitro study, MSCs obtained from bone marrow (BM), and neonatal sources such as placenta (PL), umbilical cord blood (UCB), and Wharton's jelly (WJ) were cultured under the same conditions to compare their abilities to support the formation of myeloid (dendritic cell-like/non-classical monocyte-like) and lymphoid (NK and B cells) lineages from hematopoietic progenitor cells (HPCs). MSCs were co-cultured with CD34⁺CD38^- Lin^- HPCs in the presence or absence of exogenous cytokines; cell lineages obtained were evaluated through flow cytometry. Results: Our results demonstrate that similarly to BM-MSCs, MSCs from neonatal sources have potential to support the formation of dendritic cells, non-classical monocytes, NK, and B cells. However, in contrast to BM-MSCs, neonatal sources favor the generation of lymphoid populations of advanced stages of differentiation. Conclusions: These results indicate that MSCs from neonatal sources have increased lymphopoietic potential compared to BM-MSCs, a finding with significant implications for the selection of MSC sources in clinical trial design.