Culture conditions and signalling networks promoting the establishment of cell lines from parthenogenetic and biparental pig embryos.

The generation of porcine embryonic stem cells (pESC) would potentially have great impact in the biomedical field given the long-standing history of the pig as a prime animal model for pre-clinical biomedical applications. These cells would also be beneficial for the agricultural area, allowing efficient genetic engineering of this animal, to improve health and production traits. Despite numerous reports, no conclusive results have been obtained on the isolation and propagation of pESC lines and the establishment of pluripotent cells from the pig has remained an elusive goal. In the present study we performed a systematic analysis of different culture media for their ability to support the establishment of homogenous outgrowths from in vitro-produced embryos. Furthermore, we investigated which molecular networks are responsive to the factors contained in the most efficient media, since the identification of dominant signaling pathways that regulate porcine stem-cell pluripotency is likely to facilitate the generation of genuine pESC. Finally we compared IVF blastocysts versus parthenotes as a possible source for putative pESC in terms of blastocyst rate, resilience to immunosurgery procedures, ability to attach to the feeder, to generate outgrowths and to establish stable cell lines.