Disturbance of the Epithelial-Mesenchymal Transition as a Cause of the Defective Development of Human Spontaneous Abortions with Abnormal Karyotype.

Genetic program regulating epithelial-mesenchymal transition is activated at the early stages of embryogenesis. Abnormal karyotype of the embryo disrupts the fundamental process of epithelial-mesenchymal transition, which is seen from incomplete morphological rearrangement and reduced migration capacity of cells, as well as low level of expression of epithelial-mesenchymal transition markers (fibronectin, collagen, and glycosaminoglycans). Disturbances of the epithelial-mesenchymal transition affect the proliferative potential of cells with aberrant karyotype, which contributes to the delay of embryonic development and correlates with the formation of abnormal phenotype in carriers of chromosomal abnormalities.

Screening ethnically diverse human embryonic stem cells identifies a chromosome 20 minimal amplicon conferring growth advantage.

The International Stem Cell Initiative analyzed 125 human embryonic stem (ES) cell lines and 11 induced pluripotent stem (iPS) cell lines, from 38 laboratories worldwide, for genetic changes occurring during culture. Most lines were analyzed at an early and late passage. Single-nucleotide polymorphism (SNP) analysis revealed that they included representatives of most major ethnic groups.

Correlation between preimplantation genetic diagnosis for chromosomal aneuploidies and the efficiency of establishing human ES cell lines.

There are several sources from which human embryonic stem cell (hESC) lines can be generated: surplus embryos after in vitro fertilization procedures, one- and three-pronuclear zygotes, early arrested or highly fragmented embryos that have reached the blastocyst stage, or otherwise chromosomally or genetically abnormal embryos after preimplantation genetic diagnosis (PGD). We report on the efficiency of establishing hESC lines from blastocysts with proven meiotic or mitotic errors after sequential testing of both polar bodies and blastomere analysis on day 3. The success rate of establishing hESC lines originating from blastocysts carrying a meiotic error was as low as 2.

Impact of meiotic and mitotic non-disjunction on generation of human embryonic stem cell lines.

At least 50-60% of oocytes derived from IVF procedures are chromosomally abnormal due to meiotic I or II errors. Through the use of polar body and blastomere diagnosis, euploid embryos suitable for transfer can be identified. Those embryos that are aneuploid are usually discarded, or otherwise can be used to generate chromosomally abnormal human embryonic stem cell (hESC) lines.

Cytoplasmic cell fusion: Stembrid technology for reprogramming pluripotentiality.

Recent progress in somatic cell nuclear transfer (SCNT) provides the evidence for the presence of reprogramming factors in human embryonic stem cells (hESC). Hybrid hESC with donor human somatic nuclei have been established, but the resulting hybrid hESC contained DNA originating from both hESC and donor somatic cells. There is still no method to completely replace the hESC nuclei by the nuclei of somatic cells and to obtain the pure colonies of hESC with donor genotype.