Semiquantitative histopathology and 3D magnetic resonance microscopy as collaborative platforms for tissue identification and comparison within teratomas derived from pedigreed primate embryonic stem cells.

Teratoma formation in xenografts is a sufficiently stringent pluripotency assay for stem cells. However, little is known about the composition and spatial relationships of tissues within teratomas that may provide clues about development and platforms for studying organ development. Additionally, teratoma formation and analysis lack standards for reporting as assays of pluripotency. Three of 27 total teratomas derived from pedigreed primate embryonic stem cells underwent quantitative three-dimensional high-resolution magnetic resonance microscopy (MRM). Teratomas were subsequently serially sectioned and tissue types identified, semiquantitated, and correlated with MRM images. All teratomas demonstrated tissue derivatives from the three germ layers and approximately 23 different tissue types were identified. Certain tissue groups attempted to form organs more frequently (e.g., trachea/bronchi, small intestine). MRM discriminated some tissues readily (e.g., bone, adipose, cartilage) while other tissue types with like MR intensities could not be distinguished. Semiquantitative histopathological analysis of teratomas demonstrates the ability to delineate multiple tissues as derived from ectoderm, mesoderm, or endoderm and to use this information for comparison to other teratomas. MRM provides rapid quantitative imaging of intact teratomas that complements histology and identifies sites of interest for additional biological studies.

Establishment and characterization of baboon embryonic stem cell lines: an Old World Primate model for regeneration and transplantation research.

Here we have developed protocols using the baboon as a complementary alternative Old World Primate to rhesus and other macaques which have severe limitations in their availability. Baboons are not limited as research resources, they are evolutionarily closer to humans, and the multiple generations of pedigreed colonies which display complex human disease phenotypes all support their further optimization as an invaluable primate model. Since neither baboon-assisted reproductive technologies nor baboon embryonic stem cells (ESCs) have been reported, here we describe the first derivations and characterization of baboon ESC lines from IVF-generated blastocysts. Two ESCs lines (BabESC-4 and BabESC-15) display ESC morphology, express pluripotency markers (Oct-4, hTert, Nanog, Sox-2, Rex-1, TRA1-60, TRA1-81), and maintain stable euploid female karyotypes with parentage confirmed independently. They have been grown continuously for >430 and 290 days, respectively. Teratomas from both lines have all three germ layers. Availabilities of these BabESCs represent another important resource for stem cell biologists.