Biomedical subjects

Jaroslav Mokrý

Publications and source records attributed to Jaroslav Mokrý.

7 recordsLinked to original sources

PubMed2006

Mesenchymal stem cells isolated from the human bone marrow: cultivation, phenotypic analysis and changes in proliferation kinetics.

Mesenchymal Stem Cells (MSCs) are rare elements living in various organs (e.g., bone marrow), able to differentiate into specialized tissues, such as bone, cartilage, tendon, and myocardium. Since the first description of MSCs by Fridenshtein, several investigators have shown that these cells can also differentiate into chondrocytes, adipocytes, and, at least, in rodents into skeletal myoblasts. Later on, more primitive progenitor cells were characterized, able to give rise not only to limb-bud mesoderm, but also to cells of visceral mesoderm. Those cells were named mesodermal progenitor cells (MPCs). The aim of our study was to characterize and compare the biological properties and spontaneous differentiation potential of two different cell types (MSCs and MPCs) isolated from the human vertebral body bone marrow. The results of our experiments proved that the MPCs can be expanded beyond Hayflick's limit and differed from MSCs in morphology, biological and phenotypic characteristics. Because of their high proliferative and differentiation potential, MPCs can become more attractive source of adult stem cells for therapeutic purposes.

Bone Marrow Cells↗

PubMed2006

Stem cell therapy for demyelinating disorders.

Multiple sclerosis (MS) is a progressive disease of the central nervous system (CNS) that attacks mainly young people. It leads to the progressive deterioration of the neurological status. Histopatologically, this disease is characterized by appearance of multiple foci of the demyelination in white matter of the CNS, with various grade of an axonal loss. The current treatment is targeted on moderating the inflammatory process and symptomatic therapy. In spite of all this therapy, the course of the disease often progresses. The tissue of the CNS in mammalians, including humans, is able to provide some degree of spontaneous remyelination. Unfortunatelly the extent of this process is not sufficient for the complete restoration. The support of remyelination by using the cell manipulations is the aim of many experimental studies. Theoretically, it is possible to achieve remyelination either by exogenous induction of remyelination from endogenous sources (precursor cells) or by the real transplantation of myelin-forming cells intrafocally, intracerebroventricularly or into the blood stream. In this work, we present the brief view on the recent state of this topic. We present the list of the cell types, useable for cell transplantations and the summary of the growth factors influencing the behaviour of the oligodendroglial precursors. We are considering the hampers in usage of the cell therapy of demyelinating disorders in clinics.

Animals↗

PubMed2005

Transplantation of bone marrow derived progenitor cells in acute myocardial infarction. The first results.

The intracoronary administration of autologous bone marrow cells (BMCs) has been shown to improve the left ventricle function in the course of acute myocardial infarction. Therefore we have started a clinical trial using transplantation of BMCs in the acute phase of myocardial infarction. The aim of our study is to assess the feasibility and safety of this procedure, and effect on the left ventricle function of these patients. We describe the first experience in two patients with acute myocardial infarction reperfused using direct stenting. The aspiration of bone marrow from the sternum provided sufficient amount of the cells for transplantation. No serious ischemia and no changes in coronary artery patency were detected after intracoronary infusion. The left ventricle ejection fraction was increasing throughout the time of three-month follow-up. No other complications (ventricular arrhythmias, reinfarction, thrombus formation) were detected.

Adult↗

PubMed2004

Neural stem cells transplanted into intact brains as neurospheres form solid grafts composed of neurons, astrocytes and oligodendrocyte precursors.

Neural stem cells (NSCs) are tissue-specific stem cells with self-renewal potential that can give rise to neurons and glia in vivo and in vitro. The aim of this study was to transplant NSCs as whole neurospheres into intact brain and assess the fate and phenotype of their progeny generated in vivo. We isolated NSCs from E14 foetal rat forebrains and cultured them in basic fibroblast and epidermal growth factor-supplemented serum-free medium in the form of neurospheres in vitro. Neurospheres were transplanted into the intact brains of 2 Wistar rats and after a period of 3 weeks, grafted brains were examined immunohistochemically. Neurospheres formed solid grafts that were found in the lateral ventricle and in the velum interpositum under the hippocampus. The majority of cells in the transplanted tissue were identified as beta-III-tubulin(+), NeuN(+), PanNF(+) and synaptophysin(+) neurons and were accumulated throughout the graft centre. GFAP(+) astrocytes were scattered throughout the entire graft and astrocyte processes delimited the outer and perivascular surfaces. A great number of NG2(+) oligodendrocyte precursors was detected. Nestin(+) endothelial cells were found to line capillaries growing in the transplant. These data indicate that nestin(+) NSCs prevailing in neurospheres differentiate following transplantation into nestin(-) neuronal and glial cells which confirms the multipotency of NSCs. Three weeks posttransplantation neuronal and astrocyte cells reached terminal differentiation (formation of synaptic vesicles and superficial and perivascular limiting membranes) while elements of oligodendroglial cell lineage remained immature. Grafting stem cells as non-dissociated neurospheres provide cells with favourable conditions which facilitate cell survival, proliferation and differentiation. However, in the intact brain, grafted neurosphere cells were not found to integrate with the brain parenchyma and formed a compact structure demarcated from its surroundings.

Animals↗

PubMed2004

Subependymal zone: immunohistochemically distinct compartment in the adult mammalian forebrain.

The subependymal zone (SEZ) lining lateral walls of the lateral cerebral ventricles represents the site of active neurogenesis in the brain of adult mammals. Peroxidase immunohistochemistry performed in paraffin-embedded sections reveals that structural organization of the SEZ differs from other regions in the brain. The SEZ is devoid of synapses that are abundant in the adjacent striatal neuropil. Therefore immunostaining of synaptophysin detects sharp borders of the SEZ. Using immunophenotypization, we identified cell types constituting the SEZ in the intact rat forebrain. The presence of neural progenitor/stem cells was confirmed by finding of nestin-immunopositive cells. Detection of the astroglial marker GFAP confirmed that astrocytes represented major supporting elements responsible for creating a unique microenvironment of the SEZ. One type of the astroglia participated in covering surfaces of the blood vessels and boundaries of the SEZ. The second astroglial cell type formed branched elongated tubes that enwrapped other SEZ cell types with their cytoplasmic extensions. The interior of astrocytic channels was occupied with small densely aggregated NCAM-immunoreactive neuroblasts. Bipolar morphology indicated that these cells probably underwent migration. Immunodetection of other neuronal markers like beta-III tubulin, MAP-2 and Pan neurofilaments identified positive cells in the neighbouring brain parenchyma but not in the SEZ. The rostral migratory stream (RMS) linked with the anterior SEZ had a similar structural arrangement. It contained a large amount of nestin+ and vimentin+ cells. The RMS consisted of GFAP+ astrocytic tubes ensheathing NCAM+ neuroblasts. On the contrary to the SEZ, the RMS neuroblasts expressed beta-III tubulin. However, markers of postmitotic neurons MAP-2, Pan neurofilaments and synaptophysin were not expressed in the RMS. Our study describes a complex histological structure of the rat SEZ, identifies its individual cell types and demonstrates a usefulness of immunohistochemical detection of cell-specific markers in a study of microenvironment forming neurogenic zones in the mammalian brain.

Animals↗

PubMed2003

Experimental brain injury induces activation of neural stem cells in the forebrain subependyma.

The subependymal zone (SEZ) of adult mammalians contains relatively quiescent neural stem cells that can be stimulated toward proliferation in response to specific stimuli. We used immunophenotypization to demarcate sharp boundaries of the SEZ and identify cell populations constituting the rat intact SEZ. Moreover, we studied the proliferation rates of SEZ cells under various experimental conditions that induced the lesion of the neighboring brain parenchyma or SEZ cells. Four groups of experimental animals included rats that were (1). mechanically injured, (2). intracerebrally injected with kainic acid, (3). treated with intracerebral injection of neurotoxic sodium nitroprusside, or (4). treated with intraperitoneal injection of cyclophosphamide. Animals were killed after 4 or 8 days. The number of SEZ proliferating cells was counted in coronal sections immunostained for proliferating cell nuclear antigen (PCNA) and bromodeoxyuridine. Our results show that all types of injury induced activation of SEZ neural stem cells, evidenced by the increase of corresponding proliferation indices when compared with intact brains. The increase was detected not only in ipsilateral but also in contralateral (intact) SEZ. After mechanically induced trauma of the right cerebral hemisphere, the increase in the number of SEZ proliferative cells was observed after 8 days in the right cerebral ventricle. Injection of kainic acid induced early responses in SEZ cells that reached the highest values. Injury induced by sodium nitroprusside evoked early increase of PCNA, whereas bromodeoxyuridine increase was detected in SEZ at day 8. Cyclophosphamide activated SEZ proliferation after 4 days, and the level of proliferation indices remained approximately the same at day 8. Our data suggest that each type of brain injury induces a SEZ proliferative response with a specific temporal pattern.

Animals↗

PubMed2002

Histological and histochemical analysis of embryoid bodies.

We examined the histological structure of embryoid bodies arising from aggregation of mouse embryonic stem (ES D3) cells after 7, 12, 18 and 26 days of in vitro culture. Morphology of originally solid embryoid bodies was affected by the process of cavitation that resulted in formation of cystic embryoid bodies and by spontaneous differentiation of the ES D3 cells. We applied in situ immunophenotyping to characterise cell populations that spontaneously differentiated inside the embryoid bodies in the various stages. The most distinct cell populations that were found inside embryoid bodies were alpha-fetoprotein-positive endodermal cells and myogenic cells that expressed desmin, myogenin or smooth muscle actin. ES D3-derived endothelial cells generated during vasculogenesis inside the embryoid bodies differed from mature endothelial cells because they did not stain for von Willebrand factor. These cells also differed from endothelial cell that were generated during angiogenesis since they did not stain for the intermediate filament nestin. Our results demonstrate the usefulness of this in vitro model for studying early embryogenesis.

Actins↗