Purpose: to evaluate in experiment the dynamics and intensity of vascular sprouting in the donor cornea during keratoplasty against the background of pre-existing neoangiogenesis when using a conditioned medium of mesenchymal stem cells.Materials and methods. The object of the study was 15 rabbits (10 recipient rabbits, 5 donor rabbits) of the gray Chinchilla breed weighing 2.5–3.2 kg. The experiments were carried out in two stages. At the first stage, 10 animals were simulated with a unilateral thermal burn of the peripheral zone of the cornea with limbal involvement. Penetrating keratoplasty was performed using standard technology on the 15th day of the experiment. At the second stage, the recipient rabbits were divided into experimental and control groups. 5 rabbits, 5 eyes, in the control group and 5 rabbits, 5 eyes, in the main group. In the main group, instillations of paracrine factors of mesenchymal stem cells were used as postoperative treatment from the 1st to the 30th knocks four times. In the control group, treatment was carried out by instillation of antibiotics (Oftaquix) and keratoprotectors (Korneregel) three times for 30 days. Research methods included biomicroscopy, photographic recording of the anterior segment of the eye, examination using a Pentacam AXL device, and histological examination. The observation periods were 1st, 3rd, 7th, 14th, 30th day.Results. The results of postoperative treatment at the second stage of the experiment, as well as the results of histology, showed a pronounced antiangiogenic effect of the conditioned medium of mesenchymal stem cells. This was confirmed by the absence of pronounced vascularization of the donor cornea, the attenuation of the inflammatory reaction and the formation of a scar on the 30th day of drug instillation. In the control group, graft disease developed from the seventh day.Conclusion. The results obtained during the work seem promising. The use of the conditioned medium of mesenchymal stem cells demonstrated a sufficiently pronounced effectiveness compared with standard drug therapy in the postoperative period after high-risk end-to-end keratoplasty in experimental animals performed on a model of post-burn corneal neovascularization.

Background: Acute Kidney Injury (AKI) is a severe complication of cisplatin-based chemotherapy. Thus, searching for novel therapeutic approaches to reduce system toxicity is vital for improving patient outcomes. The use of stem cells or the paracrine factors released by these cells during cultivation is currently being explored as a potential method for AKI prevention during chemotherapy. However, the conditions of stem cell cultivation considerably affect the composition of paracrine factors released by cells. Objective: In this study, we aimed to investigate the impact of paracrine factors derived from mesenchymal stem cells cultured under hypoxic conditions on the progression of AKI induced by cisplatin. Methods: AKI was induced in mice by intraperitoneal administration of cisplatin with the simultaneous injection of fractions of conditioned medium obtained from the cultivation of mesenchymal stem cells under hypoxic conditions. The survival rate of animals was assessed alongside qRTPCR implementation to assess gene expression of cytokines. Results: The total fraction of conditioned medium and >30 kDa fraction had no impact on cisplatin nephrotoxicity in mice. However, either subcutaneous or intraperitoneal administration of <30 kDa fraction of conditioned medium exacerbated animal mortality and led to severe damage to renal tissues. The effect was in a good correlation with KIM-1 and CDKN1A gene expression. Conclusion: The conditioned medium obtained during mesenchymal stem cells under hypoxic conditions has been found to markedly amplify the toxicity of cisplatin, which should be considered in stem cell therapy of AKI patients.

A mesenchymal stem cell (MSC)-derived conditioned medium (CM) was tested for effects on the severity of the systemic inflammatory response induced by acetaminophen (APAP), including its long-term influence on hepatic tissue. A CM fraction of <30 kDa showed a maximum protective effect. Proteins of the fraction reduced the systemic inflammatory response and liver tissue fibrosis long after the toxin administration. Liver tissues from experimental animals were examined, and reduction of granulocytic infiltration was found to correlate with the degree of hepatic parenchymal necrosis, which was confirmed by the cytolysis enzyme level. The <30-kDa fraction increased the spontaneous and decreased the phorbol 12-myristate 13-acetate (PMA)-induced intracellular production of reactive oxygen species (ROS). Expression of the macrophage migration inhibitory factor (MIF) and thioredoxin significantly increased as compared to controls during increased spontaneous ROS production in neutrophils.

Nitric oxide (II) (NO) is the most important mediator of a wide range of physiological and pathophysiological processes. It is synthesized by NO synthases (NOSs), which have three main isoforms differing from each other in terms of activation and inhibition features, levels of NO production, subcellular localization, etc. At the same time, all isoforms are structurally very similar, and these differences are determined by NOS autoregulatory elements. The article presents an analysis of the autoregulatory and autoinhibitory mechanisms of the NOS reductase domain that determine differences in the productivity of isoforms, as well as their dependence on the concentration of Ca2+ ions. The main regulatory elements in NOS that modulate the electron transfer from flavin to heme include calmodulin (CaM), an autoinhibitory insert (AI), and the C-terminal tail (C-tail). Hydrophobic interactions of CaM with the surface of the NOS oxidase domain are assumed to facilitate electron transfer from flavin mononucleotide (FMN). CaM binding causes a change in the inter-domain distances, a shift of AI and the C-tail, and, as a result, a decrease in their inhibitory effect. CaM also shifts the conformational equilibrium of the reductase domain towards more open conformations, reduces the lifetime of conformations, their stereometric distribution, and accelerates the flow of electrons through the reductase domain. The AI element, apparently, induces a conformational change that hinders electron transfer within the reductase domain, similar to the hinge domain in cytochrome P450. Together with CaM, the C-tail regulates the electron flow between flavins, the distance and relative orientation of isoalloxane rings, and also modulates the electron flow from FMN to the terminal acceptor. Together with the C-tail, AI also predetermines the dependence of neuronal and endothelial forms of NOS on the concentration of Ca2+ ions, and the C-tail length affects differences in the productivity of NO synthesis. The inhibitory effect of the C-tail is likely to be reduced by CaM binding due to the C-tail shift due to the electrostatic repulsive forces of the negatively charged phosphate and aspartate residues. The autoregulatory elements of NOS require further study, since the mechanisms of their interaction are complex and multidirectional, and hence provide a wide range of characteristics of the observed isoforms.

В связи с увеличением числа заболеваний, в основе которых лежит развитие новообразованных сосудов, в последние десятилетия возрос интерес к проблеме патологического ангиогенеза в различных тканях глаза. Традиционные консервативные методы лечения неоваскуляризации роговицы на данный момент недостаточно эффективны. Возможным путем решения проблемы неоваскуляризации роговицы может быть использование паракринных факторов, выделяемых мезенхимальными стволовыми клетками в процессе культивирования в кондиционированную среду (КС). Целью исследования является изучение влияния пептидов КС на сосудистое бельмо, которое сформировалось после химического ожога глаз крыс в эксперименте, и оценка влияния КС на функциональную активность нейтрофилов. Методы исследования. Исследование было выполнено на 48 крысах (48 глаз) в несколько этапов. На первом этапе всем животным был смоделирован химический ожог роговицы. На втором этапе проводилось лечение ожогов роговицы. В зависимости от способа лечения на втором этапе была сформирована контрольная группа 22 крысы (22 глаза) и опытная группа 22 крыс (22 глаза). Опытная группа была разделена на 2 подгруппы. В первой подгруппе было 11 крыс (11 глаз), которым в качестве лечения применялись пептиды КС общей фракции. Во второй подгруппе также было 11 крыс (11 глаз), в качестве лечения применялся пептиды КС фракцией до 30 кДа. В контрольной группе для лечения ожогов мы применяли культуральную среду. Результаты. По результатам офтальмоскопии и гистологических исследований на 14-е и 30-е сутки в контрольной группе животных динамики не наблюдалось. Выявлялись множественные новообразованные сосуды роговицы (преимущественно крупные сосудистые стволы) со стромальными помутнениями в их проекции. Эпителий роговицы был не изменен, однако, сама роговица была истончена. Наблюдалось сформированное васкуляризированное бельмо роговицы: субэпителиальная фиброплазия и неоваскуляризация роговицы. В опытной группе животных к 14-м суткам инстилляций в конъюнктивальную полость пептидов КС офтальмоскопически мы наблюдали уменьшение количества новообразованных сосудов, помутнения роговицы исчезли в проекции запустевших сосудов. На 30-е сутки лечения в опытных группах животных у большинства крыс новообразованных сосудов обнаружено не было, сохранялись лишь отдельные сосудистые стволы, которые ранее образовывали мощные анастамозы с другими новообразованными сосудами. По результатам хемолюминесцентного анализа показано, что фракция до 30 кДа угнетает функциональную активность нейтрофилов, в том числе за счет изменения активности внутриклеточных мембранных ферментов, отвечающих за передачу рецепторных сигналов внутрь клетки. Заключение. Полученные результаты свидетельствуют о перспективности применения препарата раствора пептидов для лечения такой сложной патологии, как неоваскуляризация роговицы. In recent decades, due to increasing number of diseases associated with the development of newly formed vessels, the interest to pathological angiogenesis in eye tissues has been growing. Traditional, conservative methods for treatment of corneal neovascularization are not sufficiently effective. A possible solution may be the use of paracrine factors secreted by mesenchymal stem cells during cultivation in a conditioned medium (CW). The aim of this study was to assess the effect of CW peptides on vascular leukoma induced by chemical burn of rat eyes and to evaluate the effect of CW on the functional activity of neutrophils. Methods. The study was performed on 48 rats (48 eyes) and included several stages. At the first stage, chemical corneal burn was modeled in all animals. At the second stage, corneal burns were treated. Based on the method of treatment at the second stage, a control group (22 rats, 22 eyes) and an experimental group (22 rats, 22 eyes) were formed. The experimental group was divided into 2 subgroups. The first subgroup rats (n = 11, 11 eyes) were treated with CW peptides of the entire fraction. The second subgroup rats (n = 11, 11 eyes) received a CW peptide fraction of up to 30 kDa. In the control group, the culture medium was used as a treatment. Results. According to the results of ophthalmoscopy and histological studies on days 14 and 30, no changes were observed in the control group. Multiple newly formed corneal vessels (mainly large vascular trunks) with stromal opacities in their projection were detected. The corneal epithelium was unchanged; however, the cornea itself was thinned. A formed vascularized corneal leukoma was observed that was evident as subepithelial fibroplasia and corneal neovascularization. In the experimental group by the 14th day of CW peptide instillations into the conjunctival cavity, ophthalmoscopy showed a decrease in the number of newly formed vessels, and corneal opacities disappeared in the projection of the deserted vessels. In most of rats in the experimental groups on the 30th day of the treatment, newly formed vessels were not found; only individual vascular trunks remained, which had previously formed powerful anastomoses with other newly formed vessels. According to the results of chemiluminescence analysis, a fraction of up to 30 kDa inhibited the functional activity of neutrophils, including by changing the activity of intracellular membrane enzymes responsible for the transmission of receptor signals into the cell. Conclusion. The results showed that the peptide solution is promising for the treatment of such a complex pathology as corneal neovascularization.

ФОРМИРОВАНИЕ СТРУКТУРНОЙ СХЕМЫ УНИВЕРСАЛЬНОЙ МОДЕЛИ КАТАЛИТИЧЕСКОГО ЦИКЛА NO-СИНТАЗ

The review considers the use of mesenchymal stem cells (MSCs) derived from various tissues in treating the conditions consequent to ischemia (circulation injury) and subsequent reperfusion (blood supply restoration) of organs and tissues. MSC modification methods to improve the treatment efficacy are described. A potential effect in treating frostbites is hypothesized for MSCs.

This study explored the effect of mesenchymal stem cells (MSC) conditioned medium (CM) on the severity of systemic inflammatory response caused by acetaminophen administration. The long-term effects of the toxin on the liver tissue were analysed. The effect of a fraction of the conditioned medium on the functional activity of isolated neutrophils was investigated using a model of sterile inflammation. The study showed that the >30 kDa CM fraction possesses the maximum protective effect. Proteins of this fraction reduce the severity of the systemic inflammatory reaction and the extent of liver tissue fibrosis after the toxin injection in the long term. By using the sterile inflammation model, CM was shown to reduce the complex activity of NADPH oxidase, which leads to a decrease in the total reactive oxygen species production. The CM derived from the cultivation of stem cells reduces the severity of the systemic inflammatory response through suppression of the functional activity of neutrophils.

An important role of immunological factors in the pathogenesis of many pathological conditions allows for their consideration as diagnostic and prognostic disease markers. A promising approach to the diagnosis of immunological abnormalities is based on the non-invasive cell diagnostic technology of quantitative phase imaging (QPI), with underlying principles of laser interferometry and holography. Our investigation is aimed to assess the QPI potential to analyze cell cytotoxicity and identify diagnostic criteria for cell immunity abnormalities in female patients with endometriosis. Measurements were performed in an original Cytoscan coherent-phase microscope (Russia). The optical scheme of the microscope is a modified Linnic microinterferometer optical scheme. He-Ne laser radiation (lambda=633 nm, 1 mWatt) passes through a semi-transparent beam splitter, the object wave passes through the analyzed object twice, while the reference wave is reflected without any wave-front aberrations by a flat mirror fixed at a piezoconverter. We studied phase interference pictures of native lymphocytes to identify morphological and densitometry characteristics for CD8+cells. Two groups of cells were identified in the cytotoxic lymphocyte population, which differed in their values of the phase thickness (Hcyt) and the area of cytoplasm adjacent to the membrane and containing the perform granules (Scyt). It was found, that in the healthy controls the proportion of perforin-positive cytotoxic CD8+lymphocytes was 37.1 +/- 5.15%, in the patients with endometriosis 29.8 +/- 6.34%. The reagent-free quantitative phase imaging technology (QPI), based on interference microscopy and holography, provides visualization, recording, monitoring, and multiparameter analysis of the data obtained in the study of living cells.

The potential use of low-temperature plasma (LTP) for therapeutic purposes has aroused the concern of many researchers. This paper examines the effect of LTP on the morphofunctional state of human bone marrow stem cells (BMSC). It has been established that LTP-induced oxidative stress has a dual effect on the state of stem cells. On the one hand, a cell culture exposed to LTP exhibits the progression of a destructive processes, which is manifested by the perturbation of the cell’s morphology, the initiation of lipid peroxidation and the accumulation of products of this process, like diene conjugates and malondialdehyde, as well as the induction of mitochondrial dysfunction, leading to cell death. On the other hand, the effect of LTP on BMSC located at a distance from the plasma is accompanied by the activation of proliferative processes, as evidenced by the tendency of the activity of mitochondrial biogenesis and fission/fusion processes to increase. The paper discusses the role of mitochondria and reactive oxygen species (ROS) in the cellular response to LTP.

We present here the results of studies of the effect of low-temperature plasma on the proliferative activity of cells and the repair functions of the biological tissues in animals and plants. The influences of low-temperature plasma on the viability and proliferative activity of human stem cells are considered. Human stem cells can undergo apoptosis or proliferate, depending on the location of the zone of action and the observation time. Treatment of plants with the low-temperature plasma-activated drug Plazmolit, using dilutions giving a high concentration, was found to suppress growth and development, while low concentrations activated growth. These study results led to the conclusion that there is a single mechanism for the processes whereby low-temperature plasma affects the proliferative activity of cells and the repair functions of biological tissues in animals and plants.

Chronic overuse of common pharmaceuticals, e.g. acetaminophen (paracetamol), often leads to the development of acute liver failure (ALF). This study aimed to elucidate the effect of cultured mesenchymal stem cells (MSCs) proteome on the onset of liver damage and regeneration dynamics in animals with ALF induced by acetaminophen, to test the liver protective efficacy of MSCs proteome depending on the oxygen tension in cell culture, and to blueprint protein components responsible for the effect. Protein compositions prepared from MSCs cultured in mild hypoxic (5% and 10% O 2) and normal (21% O 2 ) conditions were used to treat ALF induced in mice by injection of acetaminophen. To test the effect of reduced oxygen tension in cell culture on resulting MSCs proteome content we applied a combination of high performance liquid chromatography and mass-spectrometry (LC–MS/MS) for the identification of proteins in lysates of MSCs cultured at different O 2 levels. The treatment of acetaminophen-administered animals with proteins released from cultured MSCs resulted in the inhibition of inflammatory reactions in damaged liver; the area of hepatocyte necrosis being reduced in the first 24 h. Compositions obtained from MSCs cultured at lower O 2 level were shown to be more potent than a composition prepared from normoxic cells. A comparative characterization of protein pattern and identification of individual components done by a cytokine assay and proteomics analysis of protein compositions revealed that even moderate hypoxia produces discrete changes in the expression of various subsets of proteins responsible for intracellular respiration and cell signaling. The application of proteins prepared from MSCs grown in vitro at reduced oxygen tension significantly accelerates healing process in damaged liver tissue. The proteomics data obtained for different preparations offer new information about the potential candidates in the MSCs protein repertoire sensitive to oxygen tension in culture medium, which can be involved in the generalized mechanisms the cells use to respond to acute liver failure.

Peroxiredoxin 6 (Prx6) is an important antioxidant enzyme with various functions in the cell. Prx6 reduces a wide range of peroxide substrates, playing a leading role in maintaining the redox homeostasis of mammalian cells. In addition to the peroxidase activity, a phospholipase A2-like activity was demonstrated for Prx6, which plays an important role in the metabolism of membrane phospholipids. Besides that, due to its peroxidase and phospholipase activities, Prx6 participates in intracellular and intercellular signal transduction, thus triggering regenerative processes in the cell, suppressing apoptosis caused by various factors, including ischemia-reperfusion injuries. A nephroprotective effect of exogenous recombinant Prx6 administered before ischemia-reperfusion injury was demonstrated on an animal model. Exogenous Prx6 effectively alleviates the severeness of renal ischemia-reperfusion injuries and facilitates normalization of their structural and functional conditions. Infusion of exogenous Prx6 increases the survival rate of experimental animals by almost 3 times. Application of exogenous Prx6 can be an effective approach in the prevention and treatment of renal ischemia-reperfusion kidney lesions and in preserving isolated kidneys during transplantation.

Цель - изучение влияния трансплантации стромально-васкулярной фракции (СВФ), культивированных мультипотентных мезенхимальных стволовых клеток (ММСК) жировой ткани и введения паракринных факторов кондиционной среды, полученных при культивировании ММСК, на течение тяжелых местных радиационных поражений кожи. Методика. Крыс инбредной линии Wistar-Kyoto облучали на рентгеновской установке в дозе 110 Гр, при мощности дозы 20,0 Гр/мин. Напряжение на трубке 30 кВ, ток 6,1 мА, фильтр Al толщиной 0,1 мм, площадь поля облучения составляла 8,5 см2. Трансплантацию клеток СВФ жировой ткани проводили двукратно в дозах 2,2 х 106 и 3,0 х 106 на 28-е и 35-е сут после облучения, соответственно. Культивированные ММСК вводили в дозах 2,8 × 106 и 3,4 × 106 на 28-е и 35-е сут после действия радиации. Паракринные факторы кондиционной среды вводили пятикратно с 1-х по 10-е сут после облучения, подкожно по 1,0 мл (общий белок 8 мг/мл). Тяжесть лучевого поражения кожи и эффекты терапии оценивали в динамике по клиническим проявлениям, с помощью планиметрии и патоморфологических методов. Результаты. Выбранный режим радиационного воздействия вызывал тяжелые лучевые поражения кожи с длительно (до 5 мес) незаживающими язвами. Площадь лучевых язв у крыс контрольной группы в период с 28-х до 84-х сут медленно уменьшалась от 2,73±0,17 см2 до 1,52±0,17 см2, а через 4 и 5 мес после облучения составляла 0,52±0,15 см2 и 0,05±0,04 см2, соответственно. Во всех опытных группах после 84-х сут отмечалась тенденция к снижению площади лучевых язв, а через 4 мес после облучения уменьшение площади язв и снижение тяжести поражения в опытных группах по сравнению с контролем были статистически значимыми (р < 0,05). У 70-80 % крыс в опытных группах через 4 мес после облучения наблюдалась полная эпителизация радиационных ран с образованием атрофического рубца, а в контрольной группе в этот период атрофические рубцы наблюдались лишь у 40% крыс. Заключение. Трансплантация СВФ жировой ткани или культивированных ММСК, а также введение паракринных факторов кондиционной среды способствуют усилению регенераторных процессов в пораженной ткани, и могут быть в равной степени эффективны при терапии тяжелых лучевых поражений кожи в эксперименте. Aim. To study effects of stromal-vascular fraction (SVF) transplantation, cultured multipotent mesenchymal stem cells (MMSC) of adipose tissue, and administration of paracrine factors of the conditioned MMSC culture medium on the course of severe, local radiation lesions of the skin. Methods. Wistar-Kyoto rats were irradiated with X-rays at a dose of 110 Gy and a dose rate of 20.0 Gy/min. The tube voltage was 30 kV, current - 6.1 mA, filter -0.1 mm thick A1, and irradiation field area - 8.5 cm2. Transplantation of adipose tissue SVF cells was performed twice at doses of 2.2 x 106 and 3.0 x 106 on the 28th and 35th days after irradiation, respectively. Cultured MMSC was administered at doses of 2.8 x 106 and 3,4 x 106 on the 28th and 35th days after irradiation. Paracrine factors of the conditioned medium were administered five times from the 1st to the 10th day after irradiation at a dose of 1.0 ml, s.c. (total protein, 8 mg/ml). Severity of radiation damage of the skin and effects of the therapy were followed up by clinical manifestations using planar geometry and pathomorphological methods. Results. Radiation exposure under the specified conditions caused severe radiation injuries of the skin with nonhealing ulcers that persisted for up to 5 months after irradiation. In control rats the area of radiation ulcers slowly decreased between the 28th and 84th days from 2.73 ± 0.17 cm2 to 1.52 ± 0.17 cm2, respectively, and was 0.52 ± 0.15 cm2 and 0.05 ± 0.04 cm2 at 4 and 5 months after irradiation. In all experimental groups, the healing was more intensive after the 84th day with a tendency to decrease the area of radiation ulcers; at 4 months after irradiation, statistically significant decreases in the area of ulcers and severity of lesions were observed in the experimental groups compared to the control (p <0.05). At four months after irradiation, 70-80% of rats in the treatment groups showed complete epithelialization of radiation wounds with formation of an atrophic scar whereas in the control group during the same period, atrophic scars were observed only in 40% of rats. Conclusion. Transplantation of adipose-derived SVF or cultured adipose tissue MMSC as well as administration of paracrine factors of the conditioned medium contributed to the enhancement of regenerative processes in the affected tissue and can be equally effective in the treatment of severe experimental radiation lesions of the skin.

Background. In case of a corneal burn injury, cell transplantation into the damaged area must be performed within the first 12 hours, which makes it impossible to use autologous stem cells. One solution to this problem may be the use of peptides, derived from cultured stem cells in the treatment and prevention of complications in a burn eye disease. Aims: To study the dynamics of corneal tissue repair under the influence of a peptide solution on a corneal thermal burn model.Materials and methods. The study included 20 rabbits (20 eyes) of the gray Chinchilla breed weighing from 2.5 to 3.2 kg with a corneal thermal burn model. Depending on the method of treatment used, the animals were divided in two groups of 10 rabbits (10 eyes). In the experimental group, instillations of a peptide solution were used to treat corneal thermal burns; in the control treatment was carried out with a solution of moxifloxacin and gel “Solcoseryl”. On the 1st, 3rd, 7th, 14th, 30th days in each group, two animals were sacrificed to conduct a morphological study of the cornea. Results. In the experimental group, by the 30th day, according to a histological study, the inflammatory process was completed both on the surface and inside the cornea, with a tendency to restore its normal structure. In the control group of animals, significantly longer periods of corneal recovery and preservation of inflammation, despite the received therapy, were observed.Conclusions. The use of the peptide preparation is promising in the treatment of corneal thermal burn. Further research is needed in this area.

The effect of different polyoxyethylene–polyoxypropylene triblock copolymers, their concentration, and mode of action on the loading of poly-(lactic-co-glycolic acid) copolymer-based microparticles containing such medicinal agents as radachlorin (chlorin e 6 ) or ethidium bromide in mesenchymal stem cells was studied. It has been shown that medicinal agents encapsulated inside microparticles affect the loading of these particles in the cytoplasm of mesenchymal stem cells. The number of cells that absorbed the particles with chlorin e 6 is approximately two times lower than that in the experiments with ethidium bromide. It has been shown that pretreatment of microparticles with triblock copolymers is more efficient for loading them in cells compared with simultaneous introduction of triblock copolymers and particles into the culture medium. Treatment of ethidium bromide-containing microparticles with triblock copolymers is not efficient for their loading in mesenchymal stem cells compared to the control. The exception is Pluronic 123; when particles are treated with it at concentrations of 1 and 2%, the loading of particles in cells increases compared to the control by factors of approximately 11 and 5, respectively. For particles with chlorin e 6 , their pretreatment with triblock copolymers at a concentration of 4% is most efficient; the loading of the pretreated particles in cells is increased by factors of approximately 3 to 11.

Background: In our studies, it was shown that the effectiveness of the conditioned medium obtained by cultivating mesenchymal stem cells depends on the microenvironment conditions used to cultivate the cells. It was demonstrated that the conditioned medium obtained by culturing cells with low oxygen content (10%) has a much more pronounced protective effect. Methods: Protein compositions obtained from MSCs cultured under hypoxic (10% O2 hc-MSC) and normal (21% O2 nc-MSC) conditions were used to treat acute liver failure (ALF) induced in mice by acetaminophen injection. Thus, we obtained fractions normalized by volume, which predominantly contained proteins with masses > 50, 50-30, 30-10, and 10-3 kDa. Results: The data from biochemical studies have shown that only fractions from 10 to 30 kDa (hcMSC and ncMSC) significantly reduced the level of liver enzymes in the beginning of the acute period after acetaminophen administration. Mass spectrometry analysis of the proteins contained in the isolated fractions showed a sharp increase in the protein levels in the 10-30 kDa hcMSC fraction as compared with that in 10-30 kDa ncMSCs. The composition obtained from MSCs cultured at lower O2 level (fraction 10-30 kDa hcMSC) was shown to be more potent than the composition prepared from normoxic cells. Conclusion: The results have shown that a composition obtained by culturing the cells under a reduced content of O2 (10%), significantly improves the biochemical parameters, and histological arrester reduces the degree of inflammation and stimulates regenerative processes in liver, compared to both the control group and group treated with the composition that was obtained by culturing the cells under normal oxygen content.

Data on the efficiency of low-molecular peptide preparations, selected from cultivated stem cells of marrow, in the treatment of acute kidney insufficiency in experimental animals are resulted. It is demonstrated that the use of peptide preparations reliably promotes survivability of experimental animals suffering from acute kidney insufficiency.