Mesenchymal progenitor cells in human umbilical cord blood

TLDR

Haemopoiesis relies on hematopoietic stem cells and mesenchymal progenitor cells, the latter being multipotent precursors for marrow stroma and connective tissues, yet their presence in umbilical cord blood has not been fully characterized. The study aimed to determine whether umbilical cord blood can yield mesenchymal progenitor‑like cells in culture. UCB mononuclear cells were isolated and cultured to produce adherent populations that were then characterized for mesenchymal or osteoclast phenotypes. Cultured UCB mononuclear cells produced adherent cells with either osteoclast‑like or mesenchymal‑like phenotypes, the latter expressing MPC markers, and preterm cord blood yielded a higher frequency of mesenchymal progenitors than term cord blood.

Abstract

Haemopoiesis is sustained by two main cellular components, the haematopoietic cells (HSCs) and the mesenchymal progenitor cells (MPCs). MPCs are multipotent and are the precursors for marrow stroma, bone, cartilage, muscle and connective tissues. Although the presence of HSCs in umbilical cord blood (UCB) is well known, that of MPCs has been not fully evaluated. In this study, we examined the ability of UCB harvests to generate in culture cells with characteristics of MPCs. Results showed that UCB‐derived mononuclear cells, when set in culture, gave rise to adherent cells, which exhibited either an osteoclast‐ or a mesenchymal‐like phenotype. Cells with the osteoclast phenotype were multinucleated, expressed TRAP activity and antigens CD45 and CD51/CD61. In turn, cells with the mesenchymal phenotype displayed a fibroblast‐like morphology and expressed several MPC‐related antigens (SH2, SH3, SH4, ASMA, MAB 1470, CD13, CD29 and CD49e). Our results suggest that preterm, as compared with term, cord blood is richer in mesenchymal progenitors, similar to haematopoietic progenitors.