Human Umbilical Cord Mesenchymal Stem Cells Support Nontumorigenic Expansion of Human Embryonic Stem Cells

Abstract

The expansion of pluripotent human embryonic stem cells (hESCs) requires a culture on feeder layers of mouse embryonic fibroblasts (MEFs). The culture model often causes immunogenic contaminations such as xenocarbohydrate, and inevitably forms teratoma in vivo. This study tested human umbilical cord-derived mesenchymal stem cells (HUCMSCs) as the feeder for hESCs. Wharton's jelly-derived HUCMSCs showed characteristics of MSCs and were easily maintained in a culture for over 20 passages. Under the mitomycin-inhibited HUCMSC feeder, hESCs maintained the features of embryonic stem cells (pluripotency and maintenance of normal karyotypes) after a prolonged culture of more than 20 passages. Notably, in extensive trials, no teratoma was formed in xenograft in NOD/SCID mice, but subsequent resumption of teratoma formation was noted upon transient coculturing with MEFs. Interestingly, among the four pluripotency-conferring genes, MYC and OCT4 were found to be downregulated in hESCs cocultured with HUCMSCs. Results of this study supported a nontumorigenic sustained culture of hESCs and did not form teratoma in vivo.

Comparative Evaluation of Human Mesenchymal Stem Cells of Fetal (Wharton's Jelly) and Adult (Adipose Tissue) Origin during ProlongedIn VitroExpansion: Considerations for Cytotherapy

“…In contrast, in recent years, Wharton's jelly (WJ), the mesenchyme-like cushioning material found between the vessels of the UC, has been highlighted as one of the compartments of the UC tissue that harbors a particularly large population of MSCs (here termed WJSC) [14]. These cells can be easily grown in culture without the need for specific growth factors or feeder layers, even in xeno-free culture conditions [36, 37], while at the same time they have been found to secrete soluble factors that are supportive of hemopoiesis and ESC growth [38–41]. …”

Human Umbilical Cord Mesenchymal Stem Cells: A New Era for Stem Cell Therapy

“…Such nontumorigenic effect may be caused by the downregulation of the c-myc signaling (12). There are also various fetal stem cells that can also act as a feeder layer, such as stem cells derived from the placenta and amniotic fluid (7,36).…”

“…In the enzymatic digestion method, the enzymes used for digestion vary from collagenase to a combination of collagenase and hyaluronidase with or without trypsin (12,59,65). This method can provide more homogenous cell populations and more consistent cell numbers compared to the explant method.…”

“…The HUCMSCs can be a feeder layer for ESCs, with a nontumorigenic effect (12). Such nontumorigenic effect may be caused by the downregulation of the c-myc signaling (12).…”

Stem Cell Banking for Regenerative and Personalized Medicine

“…Stem cells have been identified in various anatomical locations throughout the cord tissue including the amniotic compartment, the Wharton’s jelly and the perivascular space surrounding the blood vessels [45]. Numerous papers have described various methods to isolate the stem cells contained within the CT, few of which are relatively facile; including “scraping out” the Wharton’s jelly from cut up cord pieces, isolation and digestion of the Wharton’s jelly directly, culture of cord tissue explants, culture of amnion explants, digestion of isolated blood vessels from CT, and isolation/culture of venous epithelial stem cell tissues [46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62]. Regardless of the isolation methodology used, one generally finds that the predominant stem cell population obtained is the MSC [45].…”