Previous reports have demonstrated the growth of undifferentiated human embryonic stem (HES) cells on mouse embryonic fibroblast (MEF) feeders and on laminin- or Matrigel-coated plastic surfaces supplemented with MEF-conditioned medium. These xenosupport systems run the risk of cross-transfer of animal pathogens from the animal feeder, matrix, or conditioned medium to the HES cells, thus compromising later clinical application. Here we show that human fetal and adult fibroblast feeders support prolonged undifferentiated HES cell growth of existing cell lines and are superior to cell-free matrices (collagen I, human extracellular matrix, Matrigel, and laminin) supplemented with human or MEF feeder-conditioned medium. Additionally, we report the derivation and establishment of a new HES cell line in completely animal-free conditions. Like HES cells cultured on MEF feeders, the HES cells grown on human feeders had normal karyotypes, tested positive for alkaline phosphatase activity, expressed Oct-4 and cell surface markers including SSEA-3, SSEA-4, Tra 1-60, and GCTM-2, formed teratomas in severely combined immunodeficient (SCID) mice, and retained all key morphological characteristics. Human feeder#150;supported HES cells should provide a safer alternative to existing HES cell lines in therapeutic applications.

Human embryonic stem (ES) cell lines that have the ability to self-renew and differentiate into specific cell types have been established. The molecular mechanisms for self-renewal and differentiation, however, are poorly understood. We determined the transcriptome profiles for two proprietary human ES cell lines (HES3 and HES4, ES Cell International), and compared them with murine ES cells and other human tissues. Human and mouse ES cells appear to share a number of expressed gene products although there are numerous notable differences, including an inactive leukemia inhibitory factor pathway and the high preponderance of several important genes like POU5F1 and SOX2 in human ES cells. We have established a list of genes comprised of known ES-specific genes and new candidates that can serve as markers for human ES cells and may also contribute to the "stemness" phenotype. Of particular interest was the downregulation of DNMT3B and LIN28 mRNAs during ES cell differentiation. The overlapping similarities and differences in gene expression profiles of human and mouse ES cells provide a foundation for a detailed and concerted dissection of the molecular and cellular mechanisms governing their pluripotency, directed differentiation into specific cell types, and extended ability for self-renewal. Stem Cells

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The human umbilical cord that originates from the embryo is an extra-embryonic membrane and the Wharton's jelly within it is a rich source of stem cells (hWJSCs). It is not definitely known whether these cells behave as human embryonic stem cells (hESCs), human mesenchymal stem cells (hMSC) or both. They have the unique properties of high proliferation rates, wide multipotency, hypoimmunogenicity, do not induce teratomas and have anticancer properties. These advantages are important considerations for their use in cell based therapies and treatment of cancers. In a search for properties that confer these advantages we compared a detailed transcriptome profiling of hWJSCs using DNA microarrays with that of a panel of known hESCs, hMSCs and stromal cells. hWJSCs expressed low levels of the pluripotent embryonic stem cell markers including POUF1, NANOG, SOX2 and LIN28, thus explaining why they do not produce teratomas. Several cytokines were significantly upregulated in hWJSCs including IL12A which is associated with the induction of apoptosis, thus explaining their anticancer properties. When GO Biological Process analysis was compared between the various stem cell types, hWJSCs showed an increased expression of genes associated with the immune system, chemotaxis and cell death. The ability to modulate immune responses makes hWJSCs an important compatible stem cell source for transplantation therapy in allogeneic settings without immunorejection. The data in the present study which is the first detailed report on hWJSC transcriptomes provide a foundation for future functional studies where the exact mechanisms of these unique properties of hWJSCs can be confirmed.