Mitochondrion-targeted antioxidant SkQ1 prevents rapid animal death caused by highly diverse shocks.

The response to stress involves the activation of pathways leading either to protection from the stress origin, eventually resulting in development of stress resistance, or activation of the rapid death of the organism. Here we hypothesize that mitochondrial reactive oxygen species (mtROS) play a key role in stress-induced programmed death of the organism, which we called "phenoptosis" in 1997. We demonstrate that the synthetic mitochondria-targeted antioxidant SkQ1 (which specifically abolishes mtROS) prevents rapid death of mice caused by four mechanistically very different shocks: (a) bacterial lipopolysaccharide (LPS) shock, (b) shock in response to intravenous mitochondrial injection, (c) cold shock, and (d) toxic shock caused by the penetrating cation C12TPP. Importantly, under all these stresses mortality was associated with a strong elevation of the levels of pro-inflammatory cytokines and administration of SkQ1 was able to switch off the cytokine storms. Since the main effect of SkQ1 is the neutralization of mtROS, this study provides evidence for the role of mtROS in the activation of innate immune responses mediating stress-induced death of the organism. We propose that SkQ1 may be used clinically to support patients in critical conditions, such as septic shock, extensive trauma, cooling, and severe infection by bacteria or viruses.

[Stem Cells in the Brain of Mammals and Human: Fundamental and Applied Aspects].

Brain stem cells represent an extremely intriguing phenomenon. The aim of our review is to present an integrity vision of their role in the brain of mammals and humans, and their clinical perspectives. Over last two decades, investigations of biology of the neural stem cells produced significant changes in general knowledge about the processes of development and functioning of the brain. Researches on the cellular and molecular mechanisms of NSC differentiation and behavior led to new understanding of their involvement in learning and memory. In the regenerative medicine, original therapeutic approaches to neurodegenerative brain diseases have been elaborated due to fundamental achievements in this field. They are based on specific regenerative potential of neural stem cells and progenitor cells, which possess the ability to replace dead cells and express crucially significant biologically active factors that are missing in the pathological brain. For the needs of cell substitution therapy in the neural diseases, adequate methods of maintaining stem cells in culture and their differentiation into different types of neurons and glial cells, have been developed currently. The success of modern cellular technologies has significantly expanded the range of cells used for cell therapy. The near future may bring new perspective and distinct progress in brain cell therapy due to optimizing the cells types most promising for medical needs.

Effect of cell therapy on recovery of cognitive functions in rats during the delayed period after brain injury.

We studied the effect of systemic transplantation of human stem cells from various tissues on cognitive functions of the brain in rats during the delayed period after experimental brain injury. Stem cells were shown to increase the efficacy of medical treatment with metabolic and symptomatic drugs for recovery of cognitive functions. They accelerated the formation of the conditioned defense response. Fetal neural stem cells had a stronger effect on some parameters of cognitive function 2 months after brain injury. The efficacy of bone marrow mesenchymal stem cells from adult humans or fetuses was higher 3 months after brain injury.

Cell-to-cell cross-talk between mesenchymal stem cells and cardiomyocytes in co-culture.

The goals of the study were: (1) to explore the communication between human mesenchymal stem cells (MSC) and rat cardiac myocytes resulting in differentiation of the stem cells and, (2) to evaluate the role of mitochondria in it. Light and fluorescence microscopy as well as scanning electron microscopy revealed that after co-cultivation, cells formed intercellular contacts and transient exchange with cytosolic elements could be observed. The transport of cytosolic entity had no specific direction. Noticeably, mitochondria also could be transferred to the recipient cells in a unidirectional fashion (towards cardiomyocytes only). Transmission electron microscopy revealed significant variability in both the diameter of intercellular contacting tubes and their shape. Inside of these nanotubes mitochondria-resembling structures were identified. Moreover, after co-cultivation with cardiomyocytes, expression of human-specific myosin was revealed in MSC. Thus, we speculate that: (1) transport of intracellular elements to MSC possibly can determine the direction of their differentiation and, (2) mitochondria may be involved in the mechanism of the stem cell differentiation. It looks plausible that mitochondrial transfer to recipient cardiomyocytes may be involved in the mechanism of failed myocardium repair after stem cells transplantation.

Human neural stem cells normalize rat behavior after hypoxia.

Transplants of cultured neural stem cells from human brain survived, retained multipotent activity, and produced a neuroprotective effect on degenerating neurons in the brain of adult rats subjected to hypoxic hypoxia. They normalized animal behavior and improved conditioning in two-way avoidance response paradigm in a shuttle box.

Immunohistochemical study of fetal stem/progenitor cells from human brain transplanted into traumatized spinal cord of adult rats.

Neural stem/progenitor cells from human fetal brain were grown in a tissue culture and transplanted into traumatized spinal cord of adult rats. The behavior and differentiation of transplanted cells were studied morphologically by means of histological and immunohistochemical methods and confocal microscopy. Human neural stem/progenitor cells were viable for not less than 3 months. They migrated and differentiated into neurons and glia in the traumatized spinal cord of adult rats.

Transplantation of cultured human neural stem cells in rabbits with experimental laser-induced damage to the retina.

Cultured neural stem/progenitor cells from human fetal brain were transplanted into the retrobulbar and suprachoroid space in rabbits with laser-induced damage to the retina. Transplanted cells survived, retained multipotent activity, migrated into the zone of injury, and stimulated reparation and regeneration in the traumatized retina.

Xenotransplantation of stem/progenitor cells from human fetal brain to adult rats with spinal trauma.

In vitro grown neural stem cells from human fetal brain were transplanted to adult rats with spinal trauma. The spinal cord was examined morphologically using histological and immunohistochemical methods on days 5, 15, 30, and 110. Human neural stem/progenitor cells were viable, migrated, and differentiated into neurons and glia in the traumatized spinal cord in adult rats.

Evaluation of progenitor cell cultures from human embryos for neurotransplantation.

Human neural stem cells (HNSCs) are used in studies of neural development and differentiation, and are regarded as an alternative source of tissue for neural transplantation in degenerative diseases. Selection and standardization of HNSC samples is an important task in research and clinical approaches. We evaluated embryonal brain matter obtained from human 8-12-week-old fetuses by means of flow cytometry on a panel including: nestin; vimentin; NeuN; GFAP; beta-tubulin III; CD56; N-Cad; OB-Cad; HLA-ABC; HLA-DR; CD34, and annexin. Samples from embryos of even the same gestation differ dramatically regarding neural cell development, their phenotype and viability. The samples containing the highest proportion of stem cells and multipotent progenitors of neural types, and the least of definitive cells and antigens of histocompatibility, were selected for further expansion in serum-free medium. Secondary phenotyping 14 days later revealed again a marked heterogeneity of the cultures. For the final culturing for 24 h in a serum-containing medium we selected only samples having following phenotype: nestin+, and vimentin+ no less than 25%; HLA-DR+ and CD34+ no more than 5%; GFAP+ no more than 10%; beta-tubulin+ no more than 20%; CD56+, N-Cad+, OB-Cad+, HLA-A,B,C+, and annexin+ no more than 15%; cell viability no less than 60%. Immunocytochemical study of selected samples proved that numerous neural stem cells, and neuro- and glioblasts necessary for transplantation were present. Our results demonstrate that the flow cytometry phenotyping allows the screening and standardization of HNSC samples for further expansion and transplantation.