Abstract. The level of apoptosis is increased during pregnancy. Dying cells emit DNA that remains in blood circulation and is known as cell-free DNA (cfDNA). The concentration of cfDNA can reflect the level of cell death. The present article is the result of studying cfDNA concentration and DNase I activity in the blood plasma of 40 non-pregnant women (control), 40 healthy pregnant women (over 37 weeks) and 40 pregnant women with a diagnosis of intrauterine growth restriction (IUGR). In order to explain the obtained results, a program modeling the change of cfDNA concentration under the influence of different internal and external factors was written. It was reported that, despite the fact that the level of cell death is increased, cfDNA concentration in blood can be decreased due to activation of cfDNA elimination system. A significant increase of DNase I activity has been reported in cases of IUGR. Increase in DNase I activity over a certain threshold indicates presence of pathological processes in the organism. CfDNA circulating in blood cannot be a reliable marker of increased cell death during pregnancy. Thus, assessment of the level of cell death during pregnancy should be done by simultaneous analysis of cfDNA level and DNase I activity.

Определено количество копий рибосомных повторов (рДНК) в геномах женщин с нормальной и осложненной беременностью, а также женщин, подвергшихся процедуре экстракорпорального оплодотворения (ЭКО). Кроме того, измеряли содержание GC-богатой рДНК в образцах внеклеточной ДНК (вкДНК), полученных от женщин с нормальной и осложненной беременностью. Показано, что геномы более половины женщин с патологией беременности содержали либо больше, либо меньше копий рДНК, чем у любой женщины из контрольной группы. Также обнаружено более высокое содержание рДНК во вкДНК пациенток с осложненной беременностью, что свидетельствует о наличии хронического процесса аномальной гибели клеток в группе женщин с патологией беременности. Можно сделать принципиальный вывод: поскольку беременность является тяжелой нагрузкой на организм женщины, для успешного вынашивания требуется сбалансированный биогенез рибосом. Женщины как с низкой, так и с очень высокой копийностью рДНК имеют более высокую вероятность повышенного уровня апоптоза и попадания в группу риска. Параметр «число копий рДНК в геноме женщины» может служить дополнительным прогностическим маркером потенциальных осложнений беременности у женщины. Женщины с низким или высоким количеством копий рибосомных генов в геноме нуждаются в более внимательном ведении беременности. Показатели количества копий рДНК в геномах женщин с неудачными попытками ЭКО были значимо ниже, чем в геномах двух остальных групп. Этот факт говорит о том, что копийность рДНК в геноме является одним из факторов, влияющих на успех процедуры ЭКО. Если индвивидуальное число копий рДНК в геноме женщины меньше, чем 330, высок риск неудачного ЭКО. Необходимы дальнейшие исследования данного вопроса. As pregnancy is a stressful load for a woman, any stress-resistance factor is relevant to it. According to recent reports, ribosomal gene copy number in the genome is associated with the individual stress-resistance. We determined copy numbers of ribosomal DNA (rDNA) in genomes of pregnant women with normal and complicated pregnancy, and women after in vitro fertilization (IVF) procedure. We also measured the contents of GC-rich rDNA in cell-free DNA (cfDNA) derived from normal controls and complicated pregnancy cases. We have shown that genomes of more than a half of DNA samples from women with pregnancy pathology harbor either more, or less rDNA copies than any woman from the control group. We also found higher rDNA contents in cfDNA isolated from complicated pregnancy cases suggesting the presence of a permanent cell death process in pathology cases. A principal conclusion can be made: women with low rDNA copy numbers and with very high numbers can have higher cell death rates and belong to the risk group. The parameter «rDNA copy number in woman’s genome» can be an additional prognostic marker for eventual pregnancy complications in the woman. The numbers of rDNA copies in the genomes of women with failed IVF attempts was significantly lower than in the genomes of patients with succesfull outcome, suggesting that rDNA copy number in the genome is one of the factors that affect the success of the IVF procedure. If the individual rDNA copy number is under 330, the risk of IVF failure is high. Further studies are warranted.

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In this study, the proteomic approach based on high performance liquid chromatography connected with tandem mass spectrometry (LC-MS/MS) and bioinformatics analysis were applied to identify differentially abundant proteins in chorionic villus samples (CVS) from women with blighted ovum and normal pregnancy. We identified about 600 proteins in the solubilized fraction of CVS. Comparative proteomic analysis revealed differences in the content (Average Normalized Abundances) of 187 proteins in blighted ovum. These included 134 down-regulated proteins and 53 up-regulated proteins. According to bioinformatics analysis these proteins participate in a variety of metabolic processes, including alcohol and tricarboxylic acid metabolism, response to endoplasmic reticulum stress, small molecular catabolic process, cellular respiration, and others. Proteins that demonstrated growing content in blighted ovum were mainly encoded by genes located on chromosomes 7 and 16 whereas proteins which demonstrated reducing abundance were mainly encoded by genes located on chromosomes 1, 2, and 11. We also revealed changes in the content of proteins encoded by genes located on the human chromosome 18; they are involved in apoptotic and drug metabolic processes with an important role in early pregnancy loss. Our pilot results demonstrate the efficiency of the LC-MS/MS approach for detecting the differences at the qualitative and semi-quantitative levels in the protein profiles of the CVS at anembryonic pregnancy compared to normal gestation. We conclude that globally profiled and differentially regulated proteins of CVS are helpful in obtaining molecular insights into biological processes of the pregnancy pathology.