Production of stem cells with embryonic characteristics from human umbilical cord blood

Abstract

When will embryonic stem cells reach the clinic? The answer is simple -- not soon! To produce large quantities of homogeneous tissue for transplantation, without feeder layers, and with the appropriate recipient's immunological phenotype, is a significant scientific hindrance, although adult stem (ADS) cells provide an alternative, more ethically acceptable, source. The annual global 100 million human birth rate proposes umbilical cord blood (UCB) as the largest untouched stem cell source, with advantages of naive immune status and relatively unshortened telomere length. Here, we report the world's first reproducible production of cells expressing embryonic stem cell markers, - cord-blood-derived embryonic-like stem cells (CBEs). UCB, after elective birth by Caesarean section, has been separated by sequential immunomagnetic removal of nucleate granulocytes, erythrocytes and haemopoietic myeloid/lymphoid progenitors. After 7 days of high density culture in microflasks, (10(5) cells/ml, IMDM, FCS 10%, thrombopoietin 10 ng/ml, flt3-ligand 50 ng/ml, c-kit ligand 20 ng/ml). CBE colonies formed adherent to the substrata; these were maintained for 6 weeks, then were subcultured and continued for a minimum 13 weeks. CBEs were positive for TRA-1-60, TRA-1-81, SSEA-4, SSEA-3 and Oct-4, but not SSEA-1, indicative of restriction in the human stem cell compartment. The CBEs were also microgravity--bioreactor cultured with hepatocyte growth medium (IMDM, FCS 10%, HGF 20 ng/ml, bFGF 10 ng/ml, EGF 10 ng/ml, c-kit ligand 10 ng/ml). After 4 weeks the cells were found to express characteristic hepatic markers, cytokeratin-18, alpha-foetoprotein and albumin. Thus, such CBEs are a viable human alternative from embryonic stem cells for stem cell research, without ethical constraint and with potential for clinical applications.

Identification of pulmonary Oct-4 + stem/progenitor cells and demonstration of their susceptibility to SARS coronavirus (SARS-CoV) infection in vitro

“…A recent study has shown that a few Oct-4 ϩ cells can be found scattered in the basal layer of the epidermis; however, the identity of these cells has not been determined (28). In contrast, a growing list of cells have been shown to express Oct-4, including cells growing in cultures from mouse bone marrow CD34 ϩ hematopoietic progenitors (29) and human umbilical cord blood (30), cultured epithelial cells lacking connexins and gap junctional intercellular communication (28), and mesenchymal stem cells (31,32). In the current study, we have demonstrated that the neonatal lung-derived Oct-4 ϩ epithelial colony cells also coexpress other stem cell markers such as SSEA-1 and Sca-1 but not c-Kit, CD34, and p63.…”

Umbilical cord blood banking: an update

“…In addition to hematopoietic stem cells, cord blood contains endothelial cells, mesenchymal stromal cells, T-regulatory cells, dendritic cells, and natural killer cells [44]. These cell types can become an important area to study in medicine allowing for potentially new treatment options for additional diseases or conditions [45] including brain injury [46][47][48], strokes [47,[49][50][51]], Parkinson's [52], Alzheimer's [50,53], Huntington's [54] and amyotrophic lateral sclerosis [50,55]. Other diseases in early stages of investigation include liver disorders [56], diabetes [57,58], and myocardial infarction [49,59].…”

Bone marrow‐derived very small embryonic‐like stem cells: Their developmental origin and biological significance

“…Furthermore, several groups of investigators described the presence of Oct-4 ϩ , Nanog ϩ , and SSEA-3/4 ϩ stem cells in human CB and umbilical cord matrix (Carlin et al, 2006). They were enriched by different approaches using (1) immunomagnetic beads against CD133 (Baal et al, 2004); (2) expansion of a hematopoietic cell-depleted adherent population of CB cells in the presence of thrombopoietin, kit ligand, and flt3-ligand (McGuckin et al, 2005); or (3) isolation of mononuclear cells by Ficoll gradient centrifugation (Zhao et al, 2006).…”