Analysis of Neural Stem Cells from Human Cortical Brain Structures In Vitro.

Comparative immunohistochemical analysis of the neocortex from human fetuses showed that neural stem and progenitor cells are present in the brain throughout the gestation period, at least from week 8 through 26. At the same time, neural stem cells from the first and second trimester fetuses differed by the distribution, morphology, growth, and quantity. Immunocytochemical analysis of neural stem cells derived from fetuses at different gestation terms and cultured under different conditions showed their differentiation capacity. Detailed analysis of neural stem cell populations derived from fetuses on gestation weeks 8-9, 18-20, and 26 expressing Lex/SSEA1 was performed.

Effect of multipotent stromal cells on the function of cell mitochondria in regenerating liver.

Intrasplenic allogeneic transplantation of multipotent stromal cells from the umbilical cord stimulates hepatocyte proliferation and promotes recovery of liver weight in rats after subtotal resection (80% organ weight). It can be hypothesized that this effect of multipotent stromal cells is due to more rapid recovery of the number of mitochondria and normalization of mitochondrial function of liver hepatocytes.

[Interstitial pacemaker cells].

This article is devoted to interstitial Cajal cells (syn. telocytes, interstitial pacemaker cells, IPC). First those cells were discovered by C.R Cajal in the muscle coat of the gut in 1893. Nowadays they have revealed in all parts of digestive systems (from esophagus to rectum), urinary and biliary tracts, prostate, liver, the walls of arteries and lymphatics, as well Fallopian tube, myometrium, mammary glands. Characteristic ultrastructural features are elongated spindle shape, length from 40 to 100 µm, the thickness of 0.2-0.5 µm, the presence of 2-5 processes. Length of them rangingfrom tens to hundreds of micrometers, some of them have secondary and tertiary branching, forming a three-dimensional network. IPC having spontaneous electrical (pacemaker) activity are cause to contraction of smooth muscle cells. Depending on the location of IPC have different morphological and ultrastructural characteristics. Characteristic immunohistochemical markers are CD117, CD34, S100, vimentin. IPC replay to acetylcholine, norepinephrine, estrogen, progesterone, and nitric oxide by influence ofcorresponding receptors. IPC have specific gap junctions with lymphocytes, basophiles, eosinophils, neutrophils, mast cells and dendritic cells. Grave pathology of those cells are forming gastrointestinal stromal tumors.

[Effects of human cultural neuronal and mesenchymal stem cells on the rat learning and brain state after acute hypoxia].

The aim of the study was to compare the effects of neurotransplantation of cultural neural stem cells (NSC) and mesenchymal stem cells (MSC) on the rat behaviour and brain state after acute hypoxia. It was shown that development of two-way avoidance defensive conditioning in a shuttle box improved in rats-recipients with NSC, but not MSC as compared to control. Both the transplants of NSC and transplants of MSC exert neuroprotective influence on the rat brain. NSC both in vitro (before transplantation) and in vivo (on day 27 after transplantation) gave rise to all neural cell types: stem/progenitor cells, precursors of neurons and glia, neurons and glial cells. MSC population in vitro and in vivo (on day 10 after transplantation) consisted of fibroblast-like cells which were eliminated by day 20 after transplantation and were surrounded by reactive glia. We suggest that effects of NSC may be connected with their good survival and potential to differentiate into neurons and with trophic influence on the brain of recipient, whereas MSC only have possible positive trophic effect at early stages after transplantation.

In vitro phenotypic modification of pigmented epithelium cells from human eye at early stages of development.

Multipotent characteristics of human fetal (9-11.5 weeks) pigmented epithelial retinal cells and capacity to transdifferentiation in neuronal direction were studied in vitro under different culturing conditions. The cultures were analyzed using a wide spectrum of antibodies. It was found that pigmented epithelium of human eye is a heterogeneous cell population with three subtypes differing by adhesion characteristics, migration, transdifferentiation potential, and reaction to microenvironmental factors. Subtype 1 cells steadily retain their epithelial characteristics, subtype 2 cells change their morphotype and produce neuroblast and photoreceptor cell proteins, and subtype 3 cells form free floating spheres and are capable to multipotent differentiation.

Morphological changes in the kidneys of rats with postischemic acute renal failure after intrarenal administration of fetal mesenchymal stem cells from human bone marrow.

Chronic experiments on outbred albino rats were performed to compare the dynamics of histological signs for postischemic renal injury (90-min thermal ischemia) after intraparenchymal injection of cultured fetal MSC from human bone marrow. Functional indexes of the ischemic kidney were predetermined. In the early period after ischemia (day 4), administration of human bone marrow MSC was followed by the increase in blood flow in the microcirculatory bed and decrease in the degree of alteration in renal tubules. An increase in the area of zones with histological signs for normal function of tubules was accompanied by the improvement of biochemical indexes for renal function. In the delayed period, a protective effect of cell therapy was manifested in the prevention of death of renal tubules. Mild calcification of the necrotic tubular epithelium served as a marker of this process. Human bone marrow MSC were labeled with the fluorescent probe Calcein. These cells migrated from the site of injection, spread in the interstitium, and retained viability for 7 days. During this period, some cells were incorporated into the lumen of renal tubules.

Morphofunctional study of the therapeutic efficacy of human mesenchymal and neural stem cells in rats with diffuse brain injury.

We studied the effect of transplantation of human stem cells from various tissues on reparative processes in the brain of rats with closed craniocerebral injury. Combined treatment with standard drugs and systemic administration of xenogeneic stem cells had a neuroprotective effect. The morphology of neurons rapidly returned to normal after administration of fetal neural stem cells. Fetal mesenchymal stem cells produced a prolonged effect on proliferative activity of progenitor cells in the subventricular zone of neurogenesis. Adult mesenchymal stem cells had a strong effect on recovery of the vascular bed in ischemic regions.

Molecular genetic and immunophenotypical analysis of Pax6 transcription factor and neural differentiation markers in human fetal neocortex and retina in vivo and in vitro.

Neurotransplantation of various cells, including heterotransplantation of fetal cerebral stem/progenitor cells into the eye is used in experimental studies of central nervous tissue repair during neurodegeneration. For evaluation of this approach, human fetal (weeks 9-20) stem/progenitor cells of the neocortex and retina were studied in vivo and in vitro by quantitative PCR and immunohistochemical staining. Native tissues and cultures were characterized by expression of Pax6 transcription factor (critical for the development of the retina and neocortex) and differentiation markers (nestin, betaIII-tubulin, glial fibrillary acidic protein, recoverin, NeuN, neurofilaments, Ki-67). The expression of Pax6 gene in the retina during active neurogenesis was stable and much higher than in the neocortex. In primary cultures, the pattern of Pax6 gene expression is retained and repeats that in native tissues. Immunohistochemical analysis revealed similarity of nestin and betaIII-tubulin expression in the neocortex and retina during the early (9-10 weeks) and later (20 weeks) periods and differences in cell phenotypes and their distribution. Culture studies showed that neocortical and retinal stem/progenitor cells are determined and exhibit specific differentiation characteristic of the corresponding native tissues. It can be hypothesized that heterotransplantation of the cerebral progenitor cells into the retina of experimental animals can lead to realization of their neurotrophic effect, but not to their functional integration.

Experimental intravenous cell therapy of acute and chronic renal failure.

The therapeutic effect of intravenous injection of human fetal bone marrow mesenchymal stem cells or summary culture of kidney cells were studied on models of chronic or acute renal failure in outbred albino rats. Both cell types promoted improvement and normalization of the renal function in rats with stable chronic renal insufficiency (2 weeks after kidney cell injection, 1 month after bone marrow mesenchymal stem cell injection). Renal function remained normal or subnormal during the delayed period (3-3.5 months after injection). In rats with latent stage of chronic renal insufficiency, exacerbation was induced by additional 40-min ischemia. All rats receiving intravenous injection of saline died. Improvement of the functional parameters started 2 weeks after injection of kidney cells or bone marrow mesenchymal stem cells, and normalization was observed after 1.1-5 months. During the delayed period (after 3-4 months), functional parameters retained at normal or subnormal levels. In experimental series III, all rats with acute renal failure intravenously injected with saline (control) died from uremia on days 2-4. After injection of kidney cells 50% rats survived and renal function in these animals returned to normal after 2 weeks. After injection of bone marrow mesenchymal stem cells 83% rats survived, functional parameters returned to normal after 3 weeks.

[Application of cell technologies for therapy of chronic renal insufficiency (experimental study)].

The experiments on 29 white non-inbred rats with chronic renal failure (CRF) induced by right-side nephrectomy and coagulation of 1/2-2/3 of parenchyma of the left kidney were made to study the trend in renal function after injection (into renal cortex or intravenously) of cultured stem or progenitor cells from human fetuses (total culture of fetal kidney or mesenchymal stem cells of the bone marrow). In control tests with salt solution functional indices reflected persistence of CRF. On day 4 after introduction of the fetal cells into renal parenchyma renal function improved and normalized in 2 weeks. After intravenous injection of fetal cells CRF reduced slowly, especially after injection of medullary mesenchymal cells with normalization in 1 month. 2.5-3.5 months after the injection test parameters in some rats deteriorated but remained close to normal values. Glomerular filtration after injection of stem and progenitor cells recovered better while canalicular sodium reabsorption underwent normalization but was followed by deterioration.

Functional aftereffects of intraparenchymatous injection of human fetal stem and progenitor cells to rats with chronic and acute renal failure.

Chronic renal insufficiency was modeled in rats by unilateral nephrectomy and electrocoagulation of both poles of the remaining kidney; acute renal failure was induced by 90-min clamping of the vascular pedicle of the only kidney. Injection of unfractionated culture of human fetal kidney cells or bone marrow mesenchymal stem cells into damaged kidney restored its function in rats with chronic renal insufficiency (observation period up to 2 months). After 2.5 months a relapse of chronic renal insufficiency was observed in 1 of 3 rats receiving human fetal kidney cells and in 1 of 2 animals receiving bone marrow mesenchymal stem cell culture. Injection of bone marrow mesenchymal stem cell culture to rats with acute renal failure improved recovery of renal function and prevented the death from uremia, while injection of total culture of human fetal kidney cells had virtually no effect on the course of acute renal failure.

Effect of transplantation of cultured human neural stem and progenitor cells on regeneration of the cornea after chemical burn.

We studied the effect of cultured human fetal (8-12 weeks gestation) neural stem and progenitor cells on regeneration of rabbit cornea after alkaline burn. A single subconjunctival injection of cell culture suspension after burn injury significantly accelerated regeneration of the anterior and posterior epithelium in comparison with the control group.

Functional activity of mitochondria in cultured neural precursor cells.

We studied mitochondrial transmembrane potential of neural precursor cells forming neurospheres in culture. Uneven energization of mitochondria in neurosphere cells was detected. Heterogeneity of cells by the mitochondrial potential increased with neurosphere enlargement during culturing. Decrease in the mitochondrial potential in the central cells in large spheres, presumably caused by insufficient diffusion of oxygen and nutrients, can provoke their damage and death. Population of cells with high mitochondrial potential responded to addition of the nuclear dye by a decrease in mitochondrial potential, which can indicate functioning of ABCG2 complex in these cells, characteristic of undifferentiated stem cells. These data will help to create optimum conditions for culturing of neural stem cells for the maintenance of their maximum functional and proliferative activity.

Comparative analysis of differentiation and behavior of human neural and mesenchymal stem cells in vitro and in vivo.

Comparative analysis of differentiation of human neural and mesenchymal stem cells in tissue culture and after transplantation into the brain was carried out using the same antibody set. Neural stem cells differentiated into all types of neural cells, are retained after transplantation, migrate, and form reciprocal relationships with the recipient brain. Mesenchymal stem cells were incapable of neural development under conditions of common culturing or after transplantation and retained the fibroblast-like status. Recipient filaments grew into mesenchymal stem cell transplants containing no neural cells due to local changes in the extracellular matrix at the site of transplantation.

Formation of neuroepithelial structures in culture of neural stem cells from human brain.

Dissociated fetal brain cells in a floating culture form clusters and then neurospheres, some of which contain structures shaped as cell "rosettes". The cells in these "rosettes" are arranged radially around the central cavity, in which their apical processes form desmosome-like contacts. Mitotic division of cells in the "rosettes" is associated with migration of the nuclei, similarly to division of neuroepithelial cells in the neural tube during normal embryogenesis. These cells express nestin, a marker of neural stem cells. The cells in "rosettes" found after transplantation have similar characteristics.

Characteristics of human neural stem cells in vitro and after transplantation into rat brain.

We studied the effect of culturing conditions on the fate of human neural stem cells after transplantation into rat brain. Human neural stem cells cultured in the presence of mitogens without LIF migrated along the ependyma and cerebral vessels of recipients, but to a great extent degenerated by the 20th day after transplantation. Neural stem cells cultured with LIF migrated, apart from the above mentioned pathways, in the cortex and hippocampus, well survived; proliferating cells were retained 30 days after transplantation.

Human fetal neural stem cells in rat brain: effects of preculturing and transplantation.

The fate of human fetal stem/progenitor cells transplanted into rat brain depends on conditions of preculturing (long or short) and state and site of transplantation. Human nestin-positive stem cells cultured according to the short protocol did not migrate into hypoxic and normal brain after transplantation, but actively migrated in damaged spinal cord. After transplantation of long-cultured cells into the brain mainly committed neuroblasts and solitary nestin-positive cells migrated from the site of transplantation into the brain.

Transplantation of cultured neural cells from human fetuses into the brain of rats exposed to acute hypoxia.

Neural stem cells of human brain were cultured for a long time and successfully transplanted into the brain of rats exposed to acute hypoxia. Stem and committed cells, neuroblasts, and astrocytes were revealed in transplants by immunohistochemical assay. The transplants and brain tissue were not separated with a glial barrier. Human neuroblasts widely migrated into regions of neuronal degeneration in the host brain.

[Transplantation of neural stem cells in experimental retinopathy]. / Transplantatsiia neironal'nykh stvolovykh kletok pri eksperimental'noi retinopatii.

A stable and easily reproducible model of experimental retinopathy was constructed in rabbits. The influence of transplanted neural stem cells (NSC) on the functional activity of the retina was studied. Retinopathy was provoked by 0.04 mg of kainic acid introduced intravitreously. The cultivated NSCs were transplanted into the vitreous bodies of the right (experimental) eyes, physiological solution was administered into the left (control) eyes. Clinical examinations of the eyeball in the experimental group showed less pronounced proliferative changes and a lack of gliosis, whereas, in the control group, the retina looked like tissue with fibrous changes and glial bars. An evaluation of the functional activity of the retina denoted a reliably better function of rod bipolars and Muller glias in the eyes with transplanted NSCs during the whole follow-up.

Structure of cell clusters formed in cultures of dissociated human embryonic brain.

Cell clusters in a culture of dissociated brain from human fetuses at 8-12 weeks gestation in a serum-free growth medium were studied by immunohistochemical methods and electron microscopy. Heterogeneity of cell population in culture was demonstrated. Despite the influence of proliferation-stimulating factors, cell clusters contained not only nestin-immunopositive stem cells, but also beta-tubulin-, vimentin-, and GFAP-positive cells differentiating by the neural pathway. Stem cells were localized on the surface of clusters. The percentage of stem cells in large clusters was lower than in small clusters.