title: Sheep embryonic stem-like cells transplanted in full-thickness cartilage defects.
abstract: Articular cartilage regeneration is limited. Embryonic stem (ES) cell lines provide a source of totipotent cells for regenerating cartilage. Anatomical, biomechanical, physiological and immunological similarities between humans and sheep make this animal an optimal experimental model. This study examines the repair process of articular cartilage in sheep after transplantation of ES-like cells isolated from inner cell masses (ICMs) derived from in vitro-produced (IVP) vitrified embryos. Thirty-five ES-like colonies from 40 IVP embryos, positive for stage-specific embryonic antigens (SSEAs), were pooled in groups of two or three, embedded in fibrin glue and transplanted into osteochondral defects in the medial femoral condyles of 14 ewes. Empty defect (ED) and cell-free glue (G) in the controlateral stifle joint served as controls. The Y gene sequence was used to detect ES-like cells in the repair tissue by in situ hybridization (ISH). Two ewes were euthanized at 1 month post-operatively, three each at 2 and 6 months and four at 12 months. Repairing tissue was examined by biomechanical, macroscopic, histological, immunohistochemical (collagen type II) and ISH assays. Scores of all treatments showed no statistical significant differences among treatment groups at a given time period, although ES-like grafts showed a tendency toward a better healing process. ISH was positive in all ES-like specimens. This study demonstrates that ES-like cells transplanted into cartilage defects stimulate the repair process to promote better organization and tissue bulk. However, the small number of cells applied and the short interval between surgery and euthanasia might have negatively affected the results.
authors.affiliation: AGRIS Sardegna, Laboratory of Biotechnology of Animal Reproduction, Department of Research in Animal Production, Sassari, Italy. mdattena@hotmail.com
authors.forename: Maria
authors.initials: M
authors.lastname: Dattena
authors.forename: Susanna
authors.initials: S
authors.lastname: Pilichi
authors.forename: Stefano
authors.initials: S
authors.lastname: Rocca
authors.forename: Laura
authors.initials: L
authors.lastname: Mara
authors.forename: Sara
authors.initials: S
authors.lastname: Casu
authors.forename: Gerolamo
authors.initials: G
authors.lastname: Masala
authors.forename: Lucia
authors.initials: L
authors.lastname: Manunta
authors.forename: Andrea
authors.initials: A
authors.lastname: Manunta
authors.forename: Eraldo Sanna
authors.initials: ES
authors.lastname: Passino
authors.forename: Roy R
authors.initials: RR
authors.lastname: Pool
authors.forename: Pietro
authors.initials: P
authors.lastname: Cappai
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D001755:Blastocyst / Q000166:cytology; D002356:Cartilage / Q000473:pathology*; D053595:Embryonic Stem Cells / Q000166:cytology*; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D007596:Joints / Q000601:surgery; D008297:Male; D035845:Research Embryo Creation; D012732:Sex Determination Analysis; D012756:Sheep; D033581:Stem Cell Transplantation; D014945:Wound Healing