[Pluripotent stem cells: maintenance of genetic and epigenetic stability and prospects of cell technologies].

Permanent lines of pluripotent stem cells can be obtained from humans and monkeys using different techniques and from different sources--inner cell mass of the blastocyst, primary germ cells, parthenogenetic oocytes, and mature spermatogonia--as well as by transgenic modification of various adult somatic cells. Despite different origin, all pluripotent lines demonstrate considerable similarity of the major biological properties: active self-renewal and differentiation into various somatic and germ cells in vitro and in vivo, similar gene expression profiles, and similar cell cycle structure. Ten years of intense studies on the stability of different human and monkey embryonic stem cells demonstrated that, irrespective of their origin, long-term in vitro cultures lead to the accumulation of chromosomal and gene mutations as well as epigenetic changes that can cause oncogenic transformation of cells. This review summarizes the research data on the genetic and epigenetic stability of different lines of pluripotent stem cells after long-term in vitro culture. These data were used to analyze possible factors of the genome and epigenome instability in pluripotent lines. The prospects of using pluripotent stem cells of different origin in cell therapy and pharmacological studies were considered.

[The effect of the duration of culturing on the pluripotency of mouse embryonic stem (ES) cells in vitro and in vivo]. / Vliianie dlitel'nosti kul'tivirovaniia na pliuripotentnost' émbrional'nykh stvolovykh (ES) kletok myshi in vitro i in vivo.

A comparative analysis of two clones of mouse embryonic stem cells (ES-D3) that underwent different number of passages was performed to determine their potencies for in vitro and in vivo development. Cells of both clones had similar morphology characteristic of undifferentiated ES cells and were capable of forming embryoid bodies in the suspension cultures. Specific alkaline phosphatase activity of ES cells was revealed by cytochemical staining. Karyotyping showed that the proportion of aneuploid ES cells increases with an increase in the number of passages. The results of experiments on chimera production using ES cells showed that the clone D3W (passage 17) is superior to the clone D3M (passage 42) in terms of both the proportion of chimeras produced and the degree of coat color chimerism in them.

[An analysis of chimeric mice obtained by the injection of the inner cell mass into the blastocyst]. / Analiz khimernykh myshei, poluchennykh putem in''ektsii kletok vnutrennei kletochnoi massy v blastotsistu.

Mouse chimeras were produced using injections of ICM cells into blastocysts. Chimerism of resulting animals was determined by their coat color and spectrum of glucosephosphate isomerase isoenzymes. The use of modifications of the injection method for solving different genetic and embryological problems is discussed.