Differentiation of encapsulated embryonic stem cells after transplantation.
BACKGROUND
Embryonic stem cells (ESC) when transplanted into recipients with different major histocompatibility antigens may be rejected, especially as cells differentiate and expression of these antigens increases. One method to prevent rejection is to place the developing ESC in microcapsules. It is currently unknown what effect encapsulation has on the ability of ESC to differentiate.


METHODS
Human ESC (hESC; hES03 line) and mouse ESC (mESC; R1 line) were encapsulated in 2.2% barium alginate and transplanted intraperitoneally in SCID and BALB/c mice respectively. Cell morphology, viability, and gene characterization were assessed after retrieving the capsules up to four weeks from SCID mice and three months from BALB/c mice.


RESULTS
Encapsulation prevented hESC and mESC from forming teratomas up to four weeks and three months, respectively. mESC but not hESC formed aggregates within the capsules, which remained free of fibrosis. Some but not all the transplanted encapsulated hESC differentiated towards all three lineages, but more so towards an endodermal lineage as shown by increased expression of alpha fetoprotein. This was similar to what occurred when encapsulated and non-encapsulated hESC were cultured in vitro for two weeks. In contrast to the hESC, transplanted encapsulated mESC differentiated mostly towards an ectodermal lineage as shown by increased expression of nestin and glial fibrillary acidic protein. In vitro, encapsulated and nonencapsulated mESC also began to differentiate, but not down any specific lineage.


CONCLUSIONS
Encapsulated ESC do differentiate, although along multiple pathways, both when transplanted and maintained in culture, just as nonencapsulated ESC do when removed from their feeder layer.
Dean
Sophia K
SK
Diabetes Transplant Unit, Prince of Wales Hospital, and The University of New South Wales, Sydney, Australia.
Yulyana
Yulyana
Y
Williams
Georgia
G
Sidhu
Kuldip S
KS
Tuch
Bernard E
BE
D000464:Alginates / Q000008:administration & dosage / Q000737:chemistry; D000818:Animals; D001672:Biocompatible Materials / Q000008:administration & dosage / Q000737:chemistry; D002214:Capsules / Q000008:administration & dosage / Q000737:chemistry; D002454:Cell Differentiation / Q000235:genetics; D002478:Cells, Cultured; D053595:Embryonic Stem Cells / Q000166:cytology* / Q000502:physiology / Q000637:transplantation*; D015870:Gene Expression; D020869:Gene Expression Profiling; D020723:Glucuronic Acid / Q000008:administration & dosage / Q000737:chemistry; D006603:Hexuronic Acids / Q000008:administration & dosage / Q000737:chemistry; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D016513:Mice, SCID; D020133:Reverse Transcriptase Polymerase Chain Reaction; D033581:Stem Cell Transplantation / Q000379:methods*
D000464:Alginates; D001672:Biocompatible Materials; D002214:Capsules; D006603:Hexuronic Acids; D020723:Glucuronic Acid