Cord Blood Lin−CD45− Embryonic-Like Stem Cells Are a Heterogeneous Population That Lack Self-Renewal Capacity

Abstract

Human umbilical cord blood (hUCB) has been proposed to contain not only haematopoietic stem cells, but also a rare pluripotent embryonic-like stem cell (ELSc) population that is negative for hematopoietic markers (Lin−CD45−) and expresses markers typical of pluripotent cells. The aim of this work was to isolate, characterise and expand this ELSc fraction from hUCB, as it may provide a valuable cell source for regenerative medicine applications. We found that we could indeed isolate a Lin−CD45− population of small cells (3–10 µm diameter) with a high nucleus to cytoplasm ratio that expressed the stem cell markers CD34 and CXCR4. However, in contrast to some previous reports, this fraction was not positive for CD133. Furthermore, although these cells expressed transcripts typical of pluripotent cells, such as SOX2, OCT3/4, and NANOG, they were not able to proliferate in any of the culture media known to support stem cell growth that we tested. Further analysis of the Lin−CD45− population by flow cytometry showed the presence of a Lin−CD45−Nestin+ population that were also positive for CD34 (20%) but negative for CXCR4. These data suggest that the Lin−CD45− stem cell fraction present in the cord blood represents a small heterogeneous population with phenotypic characteristics of stem cells, including a Lin−CD45−Nestin+ population not previously described. This study also suggests that heterogeneity within the Lin−CD45− cell fraction is the likely explanation for differences in the hUCB cell populations described by different groups that were isolated using different methods. These populations have been widely called “embryonic-like stem cell” on the basis of their phenotypical similarity to embryonic stem cells. However, the fact they do not seem to be able to self-renew casts some doubt on their identity, and warns against defining them as “embryonic-like stem cell” at this stage.

Implementing a routine flow cytometry assay for nucleated red blood cell counts in cord blood units

“…CD71‐negative events are probably late NRBCs, which cease to express CD71 just before losing their nucleus . A small proportion could also be related to rare cell populations recently reported in human cord blood . Besides, this gating strategy was verified using a reference control (Stak‐Chex Plus Retics; Streck Somagen).…”

Significant Improvement in Ejection Fraction and Functional Class after Two Years of Cells Transplantation

“…Thus, hematopoietic and mesenchymal stem cells from bone marrow through paracrine effects, autocrine and endocrine and together with other cells as telocytes [15,[18][19][20][21], cardiomyocytes and macrophages can promote cardiac tissue regeneration and neovascularization in the heart [2,3]. Thus, the cardiac function can be improved with an average 23% increase in the ejection fraction to 43% and also functional class improved several clinical trials according to the American Heart Association [4,10]. However, there are many flaws of standardized responses to the cell therapy efficiency worldwide, being necessary to increase the randomized multicenter studies, making it clear that there is an information gap cell therapy.…”

Cardiomyopathy and Cell Therapy: Ejection Fraction Improvement and Cardiac Muscle Mass Increasing, after a Year of Bone Marrow Stem Cells Transplantation, by Magnetic Resonance Image

“…Magnetic resonance imaging (MRI) is the best suited to meet such broad objective thanks to its resolution and clinical applicability [35]. The use of non-invasive imaging modalities in pre clinical cell therapy studies revealed key aspects of cell biology that will not be observed by other approaches excepted for histological analysis [36,37].…”

“…The aim of this study is to identify short-term result of cell transplantation in idiopathic dilated cardiomyopathy patients (IDC) who were treated by intracoronary transplantation of autologous bone marrow mononuclear cells (BMMC) and compare these results with the placebo (PL) group, by magnetic resonance imaging [33][34][35][36][37][38].…”