Available human feeder cells for the maintenance of human embryonic stem cells.

Mouse embryonic fibroblasts (MEFs) have been previously used as feeder cells to support the growth of human embryonic stem cells (hESCs). In this study, human adult uterine endometrial cells (hUECs), human adult breast parenchymal cells (hBPCs) and embryonic fibroblasts (hEFs) were tested as feeder cells for supporting the growth of hESCs to prevent the possibility of contamination from animal feeder cells. Cultured hUECs, hBPCs and hEFs were mitotically inactivated and then plated. hESCs (Miz-hES1, NIH registered) initially established on mouse feeder layers were transferred onto each human feeder layer and split every 5 days. The morphology, expression of specific markers and differentiation capacity of hESCs adapted on each human feeder layer were examined. On hUEC, hBPC and hEF feeder layers, hESCs proliferated for more than 90, 50 and 80 passages respectively. Human feeder-based hESCs were positive for stage-specific embryonic antigen (SSEA)-3 and -4, and Apase; they also showed similar differentiation capacity to MEF-based hESCs, as assessed by the formation of teratomas and expression of tissue-specific markers. However, hESCs cultured on hUEC and hEF feeders were slightly thinner and flatter than MEF- or hBPC-based hESCs. Our results suggest that, like MEF feeder layers, human feeder layers can support the proliferation of hESCs without differentiation. Human feeder cells have the advantage of supporting more passages than when MEFs are used as feeder cells, because hESCs can be uniformly maintained in the undifferentiated stage until they pass through senescence. hESCs established and/or maintained under stable xeno-free culture conditions will be helpful to cell-based therapy.