Stem Cell

Low back pain and degenerative disc disease are a significant cause of pain and disability worldwide. Advances in regenerative medicine and cell-based therapies, particularly the transplantation of mesenchymal stem cells and intervertebral disc chondrocytes, have led to the publication of numerous studies and clinical trials utilising these biological therapies to treat degenerative spinal conditions, often reporting favourable outcomes. Stem cell mediated disc regeneration may bridge the gap between the two current alternatives for patients with low back pain, often inadequate pain management at one end and invasive surgery at the other. Through cartilage formation and disc regeneration or via modification of pain pathways stem cells are well suited to enhance spinal surgery practice. This paper will systematically review the current status of basic science studies, preclinical and clinical trials utilising cellbased therapies to repair the degenerate intervertebral disc. The mechanism of action of transplanted cells, as well as the limitations of published studies, will be discussed.

Autophagy, a lysosomal degradation pathway for cellular constituents and organelles, is an adaptive and essential process required for cellular homeostasis. Although autophagy functions as a survival mechanism in response to cellular stressors such as nutrient or growth factor deprivation, it can also lead to a non-apoptotic form of programmed cell death (PCD) called autophagyinduced cell death or autophagy-associated cell death (type II PCD). Current evidence suggests that cell death through autophagy can be induced as an alternative to apoptosis (type I PCD), with therapeutic purpose in cancer cells that are resistant to apoptosis. Thus, modulating autophagy is of great interest in cancer research and therapy. Natural polyphenolic compounds that are present in our diet, such as rottlerin, genistein, quercetin, curcumin, and resveratrol, can trigger type II PCD via various mechanisms through the canonical (Beclin-1 dependent) and non-canonical (Beclin-1 independent) routes of autophagy. The capacity of these compounds to provide a means of cancer cell death that enhances the effects of standard therapies should be taken into consideration for designing novel therapeutic strategies. This review focuses on the autophagy-and cell death-inducing effects of these polyphenolic compounds in cancer.

Biological consequences and physical complaints were compared for donors randomly assigned either to blood stem cell (BSC) or bone marrow (BM) donation. In the period 1994-1999, 61 consecutive donors were included. The BSC donors were given G-CSF 10 g/kg s.c., daily during 5 days before the first leukapheresis. Nineteen donors had one leukapheresis, 10 required two and one donor needed three leukaphereses in order to reach the target cell number of 2 ؋ 10 6 CD34 + cells/kg bw of the recipient. A median platelet nadir of 102 ؋ 10 9 /l was reached shortly after the last leukapheresis. Three weeks post harvest, 17 of 30 BSC donors had a mild leukopenia. Six had a leukopenia lasting more than a year before returning to normal values. Both groups were monitored prospectively through a standardised questionnaire completed by the donors. BSC donation was significantly less burdensome than BM donation and was preferred by the donors. The short-term risks of BSC mobilisation and harvest seem negligible. The potential long-term effects of G-CSF are unresolved and the donors must be followed closely.

Background. The interests in mesenchymal stem cells (MSCs) and their application in cell therapy have resulted in a better understanding of the basic biology of these cells. Recently hypoxia has been indicated as crucial for complete chondrogenesis. We aimed at analyzing bone marrow MSCs (BM-MSCs) differentiation capacity under normoxic and severe hypoxic culture conditions.Methods. MSCs were characterized by flow cytometry and differentiated towards adipocytes, osteoblasts, and chondrocytes under normoxic or severe hypoxic conditions. The differentiations were confirmed comparing each treated point with a control point made of cells grown in DMEM and fetal bovine serum (FBS).Results. BM-MSCs from the donors displayed only few phenotypical differences in surface antigens expressions. Analyzing marker genes expression levels of the treated cells compared to their control point for each lineage showed a good differentiation in normoxic conditions and the absence of this differentiatio...

We report six patients with acute leukemia characterized by the presence of a t(lo;ll) (pl l-p15;q13-q23), either as sole cytogenetic abnormality (three patients) or as part of a complex abnormal karyotype. The morphologic and cytochemical features of four patients were consistent with FAB-M5A, while two patients presented with FAB-Ll characteristics. By immunophenotyping, myeloid leukemia

With this letter, we wish to raise caution about interpretations of results owing to artifacts that may occur when cell lines are derived by culturing on cell-derived feeder layers. We recently reported the apparent derivation of rat liver progenitor cell lines by co-culture of liver cells enriched in periportal oval cells after allyl alcohol injury with ␥-irradiated mouse STO (SIM [Sandoz inbred Swiss mouse]) fibroblast feeder layers. 1 These reported lines are now undergoing intensive reinvestigation in our laboratories and the results indicate that the cells were actually derived from the STO feeder layers. In a series of first stage RT-PCR and PCR, aimed at extending the key original findings of constitutive and inducible differentiation, we were unable to detect rat genes or rat gene products in any of the 11 reported cell strains and lines, including the clonal "rat" line 3(8)#21, and its clonal derivative 3(8)#21-EGFP, a line transduced with enhanced green fluorescent protein. Instead, only mouse genes were detected in all instances. These results were obtained both with purified and cloned putative "rat liver progenitor" cells grown on or off STO feeder layers (␥irradiated at UCSD), and with the original frozen "rat" cells obtained from untampered-with vials derived from very early passages at the Albany Medical College. These and other unexpected observations, which tend to eliminate cell fusion as the source of this artifact, are described in detail elsewhere. 2 Ongoing observations of hepatocytic functions in these lines suggest that some aspects of the original report may yet be correct. For example, the line best characterized, 3(8)#21-EGFP, expresses several hepatocyte properties in vitro and following transplantation (manuscript in preparation). In conclusion, this surprising and previously unreported type of cell culture artifact should be considered by all investigators of cultured stem cell systems which require co-culture with mitotically "inhibited" feeder layer cell lines.

Sox2 has yet to be determined. Sox2 can act synergistically with Oct3/4 in vitro to activate Oct-Sox enhancers, which regulate the expression of pluripotent stem cellspecific genes, including Nanog, Oct3/4 and Sox2 itself. These findings suggest that Sox2 is required by ES cells for its Oct-Sox enhancer activity. Using inducible Sox2-null mouse ES cells, we show that Sox2 is dispensable for the activation of these Oct-Sox enhancers. In contrast, we demonstrate that Sox2 is necessary for regulating multiple transcription factors that affect Oct3/4 expression and that the forced expression of Oct3/4 rescues the pluripotency of Sox2-null ES cells. These results indicate that the essential function of Sox2 is to stabilize ES cells in a pluripotent state by maintaining the requisite level of Oct3/4 expression.

This protocol describes the immunofluorescence staining of floating neurospheres in culture plates. Although this protocol is similar to conventional immunofluorescence staining, the staining procedure of floating neurospheres in multiwell culture plates and the washing procedure are different. Neurospheres in culture plates are transferred to a 12-well plate using a 200-1000 L pipette. The spheres are precipitated by gravity for 3 min. Then, the 12-well plate is tilted slightly, and the culture medium is aspirated by the pipette. After aspiration, the spheres are visually verified to be at the bottom of the wells. PBS (400 L) is added to the well for washing the spheres. This procedure is repeated three times. This protocol is easier than a conventional procedure using cryostat sections and can give clear sphere structures.

When it comes to public opinion about controversial issues related to science and technology, many policy makers and scientists assume that increased public understanding of science will lead to increased public support. Yet, instead of a fully informed and deliberative public, past research indicates that it is more likely that the public by nature is 'miserly', with individuals relying on their value predispositions and only the information most readily available to them from the mass media and other sources in order to formulate an opinion about science controversy. Building on this latter 'accessibility' or 'memorybased' model of opinion formation, this study tests the relationship between an increase in available information-or increasing 'awareness'-and public support for embryonic stem cell research. An analysis of national survey data collected in the USA during the fall of  and the fall of  indicates that although an increase in awareness leads to an increase in support for research, both religious and ideological value predispositions strongly moderate the impact of awareness.

Tissue stem cells have been linked to cancers of epithelial origin including the prostate. There are three relevant issues concerning stem cells and cancer that rely solely on functional studies: 1. Are there tissue-regenerating stem cells in the adult organ? 2. Can tissue-regenerating cells serve as targets for transformation? 3. Do primary tumors contain tumor-propagating (cancer stem) cells? We will review the recent literature with respect to these critical issues to provide a direct link between primitive cells and prostate cancer.

We have developed a novel three-dimensional (3D) cellular microarray platform to enable the rapid and efficient tracking of stem cell fate and quantification of specific stem cell markers. This platform consists of a miniaturized 3D cell culture array on a functionalized glass slide for spatially addressable high-throughput screening. A microarray spotter was used to deposit cells onto a modified glass surface to yield an array consisting of cells encapsulated in alginate gel spots with volumes as low as 60 nL. A method based on an immunofluorescence technique scaled down to function on a cellular microarray was also used to quantify specific cell marker protein levels in situ. Our results revealed that this platform is suitable for studying the expansion of mouse embryonic stem (ES) cells as they retain their pluripotent and undifferentiated state. We also examined neural commitment of mouse ES cells on the microarray and observed the generation of neuroectodermal precursor cells characterized by expression of the neural marker Sox-1, whose levels were also measured in situ using a GFP reporter system. In addition, the high-throughput capacity of the platform was tested using a dual-slide system that allowed rapid screening of the effects of tretinoin and fibroblast growth factor-4 (FGF-4) on the pluripotency of mouse ES cells. This high-throughput platform is a powerful new tool for investigating cellular mechanisms involved in stem cell expansion and differentiation and provides the basis for rapid identification of signals and conditions that can be used to direct cellular responses. Biotechnol. Bioeng. 2010; 106: 106–118. © 2010 Wiley Periodicals, Inc.

Hox genes are clearly implicated in leukemia; however, neither the specificity of the leukemogenic potential among Hox genes of different paralog groups nor the role of the homeodomain is clear. We tested the leukemogenic potential of various NUP98-Hox fusion genes alone and with MEIS1. All genes tested had a significant overlapping effect in bone marrow cells in vitro. However, not all formed strong leukemogenic NUP98 fusion genes; but together with overexpression of MEIS1, all induced myeloid leukemia. This phenomenon was also seen with NUP98 fusions containing only the homeodomain of the corresponding Hox protein. We then exploited the strong transforming potential of NUP98-HOXD13 and NUP98-HOXA10 to establish preleukemic myeloid lines composed of early myeloid progenitors with extensive in vitro self-renewal capacity, short-term myeloid repopulating activity, and low propensity for spontaneous leukemic conversion. We also showed that MEIS1 can efficiently induce their conversion to leukemic stem cells, thus providing a novel model for the study of leukemic progression. In contrast to the leukemogenic effect of most of the Hox genes tested, HOXB4 has the ability to increase the self-renewal of hematopoietic stem cells without disrupting normal differentiation. On the basis of the discovery that the leukemogenic gene HOXA9 can also expand hematopoietic stem cells, we compared the ability of NUP98-Hox fusions to that of HOXB4 to trigger HSC expansion in vitro. Our preliminary results indicate that the expanding potential of HOXB4 is retained and even augmented by fusion to NUP98. Moreover, even greater expansion may be possible using Abd-B-like Hox fusions genes.

Analyses of genome orthologs in cancer on the background of tumor heterogeneity, coupled with the recent identification that the tumor propagating capacity resides within a very small fraction of cells (the tumor stem cells-TSCs), has not been achieved. Here, we describe a strategy to explore genetic drift in the mitochondrial genome accompanying varying stem cell dynamics in epithelial ovarian cancer. A major and novel outcome is the identification of a specific mutant mitochondrial DNA profile associated with the TSC lineage that is drastically different from the germ line profile. This profile, however, is often camouflaged in the primary tumor, and sometimes may not be detected even after metastases, questioning the validity of whole tumor profiling towards determining individual prognosis. Continuing mutagenesis in subsets with a mutant mitochondrial genome could result in transformation through a cooperative effect with nuclear genes - a representative example in our study is a tumor suppressor gene viz. cAMP responsive element binding binding protein. This specific profile could be a critical predisposing step undertaken by a normal stem cell to overcome a tightly regulated mutation rate and DNA repair in its evolution towards tumorigenesis. Our findings suggest that varying stem cell dynamics and mutagenesis define TSC progression that may clinically translate into increasing tumor aggression with serious implications for prognosis.

Periodic chronic myelogenous leukemia (PCML) is an interesting dynamical disease of the hematopoietic system in which oscillating levels of circulating leukocytes, platelets and/or reticulocytes are observed. Typically all of these three differentiated cell types have the same oscillation period, but the relation of the oscillation mean and amplitude to the normal levels is variable. Given the appearance of the abnormal Philadelphia chromosome in all of the nucleated progeny of the hematopoietic stem cells (HSCs), the most parsimonious conclusion is that chronic myelogenous leukemia, and its periodic variant, arise from derangements partially involving the dynamics of the stem cells. Here, we have synthesized several previous mathematical models of HSC dynamics, and models for the regulation of neutrophils, platelets and erythrocytes into a comprehensive model for the regulation of the hematopoietic system. Based on estimates of parameters for a typical normal human, we have systematically explored the changes in some of these parameters necessary to account for the quantitative data on leukocyte, platelet and reticulocyte cycling in 11 patients with PCML. Our results indicate that the critical model parameter changes required to simulate the PCML patient data are an increase in the amplification in the leukocyte line, an increase in the differentiation rate from the stem cell compartment into the leukocyte line, and the rate of apoptosis in the stem cell compartment. Our model system is particularly sensitive to changes in stem cell apoptosis rates, suggesting that changes in the numbers of proliferating stem cells may be important in generating PCML. r

Lately, understanding the role of cancer stem cells in tumor initiation and progression became a major focus in stem cell biology and in cancer research. Considerable efforts, such as the recent studies by Honeth and colleagues, published in the June issue of Breast Cancer Research, are directed towards developing clinical applications of the cancer stem cell concepts. This work shows that the previously described CD44+CD24-stem cell phenotype is associated with basal-type breast cancers in human patients, in particular BRCA1 inherited cancers, but does not correlate with clinical outcome. These very interesting findings caution that the success of our efforts in translating cancer stem cell research into clinical practice depends on how thorough and rigorous we are at characterizing these cells. This ground breaking work had tremendous impact in both the stem cell field and in cancer research. At this point, it is of paramount importance to investigate the universality of these new concepts. Given the small number of tumors analyzed in the study by Clarke and colleagues [3] and the character

To identify adult human buccal epithelial stem cells (SCs) on the basis of two parameters (high p63 expression and greater nucleus/cytoplasmic (N/C) ratio) and to evaluate clinical efficacy of ex-vivo expanded autologous epithelium in bilateral limbal SC-deficient (LSCD) patients. The epithelial cells were isolated from buccal biopsy and cultured on human amnion in culture inserts with 3T3 feeder layer. The SCs were identified on the basis of two-parameter analysis using confocal microscopy, surface markers, and colony-forming efficiency (CFE). The cultured epithelium was transplanted in 10 LSCD patients followed by penetrating keratoplasty in 4 patients. The clinical outcome was followed up to 3 years. A distinct population (3.0±1.7%) of small cells expressing high levels of p63 with greater N/C ratio was observed in buccal epithelium. The N/C ratio was found to be more appropriate than cell diameter for two-parameter analysis. These cells located in the basal layer were negative f...

In this study, we describe a role for the mammalian Numb-interacting protein 1 (Nip1) in regulation of neuronal differentiation in stem cells. The expression of Nip1 was detected in the developing mouse brain, embryonic stem cells, primary neuronal stem cells, and retinoic acid-treated P19 embryonal carcinoma cells. The highest expression of Nip1 was observed in undifferentiated neuronal stem cells and was associated with Duox1-mediated reactive oxygen species ROS production. Ectopic nip1 expression in P19 embryonal carcinoma cells induced neuronal differentiation, and this phenotype was also linked to elevated ROS production.

Over the past few years, substantial progress has been made in the field of stem cell regeneration of the intervertebral disc. Autogenic mesenchymal stem cells in animal models can arrest intervertebral disc degeneration or even partially regenerate it and the effect is suggested to be dependent on the severity of degeneration. Mesenchymal stem cells (MSCs) are able to escape alloantigen recognition which is an advantage for allogenic transplantation. A number of injectable scaffolds have been described and various methods to pre-modulate MSCs’ activity have been tested. In future, work will need to address the use of mesenchymal stem cells in large animal models and the fate of the implanted mesenchymal stem cells, particularly in the long term, in animals. This review examines the state-of-the-art in the field of stem cell regeneration of the intervertebral disc, and critically discusses, with scientific support, the issues involved, before stem cells could be used in human subjects.

Cytomics aims to determine the molecular phenotype of single cells. Within the context of the -omics, cytomics allows the investigation of multiple biochemical features of the heterogeneous cellular systems known as the cytomes. Cytomics can be considered as the science of single cell-based analyses that links genomics and proteomics with the dynamics of cell and tissue function, as modulated by external inXuences. Inherent to cytomics are the use of sensitive, scarcely invasive, Xuorescence-based multiparametric methods and the event-integrating concept of individual cells to understand the complexity and behaviour of tissues and organisms. Among cytomic technologies, Xow cytometry, confocal laser scanning microscopy and laser capture microdissection are of great relevance. Other recent technologies based on single cell bioimaging and bioinformatic tools become important in drug discovery and toxicity testing, because of both highcontent and high-troughput. The multiparametric capacity of cytomics is very useful for the identiWcation, characterization and isolation of stem cell populations. In our experience, Xow cytometry is a powerful and versatile tool that allows quantitative analysis of single molecules, prokaryotic and eukaryotic cells for basic, biotechnological, environmental and clinical studies. The dynamic nature of cytomic assays leads to a real-time kinetic approach based on sequential examination of diVerent single cells from a population undergoing a dynamic process, the in Xuxo level. Finally, cytomic technologies may provide in vitro methods alternative to laboratory animals for toxicity assessment.

The differentiation and proliferation of neural stem/progenitor cells (NPCs) depend on various in vivo environmental factors or cues, which may include an endogenous electrical field (EF), as observed during nervous system development and repair. In this study, we investigate the morphologic, phenotypic, and mitotic alterations of adult hippocampal NPCs that occur when exposed to two EFs of estimated endogenous strengths. NPCs treated with a 437 mV/mm direct current (DC) EF aligned perpendicularly to the EF vector and had a greater tendency to differentiate into neurons, but not into oligodendrocytes or astrocytes, compared to controls. Furthermore, NPC process growth was promoted perpendicularly and inhibited anodally in the 437 mV/mm DC EF. Yet fewer cells were observed in the DC EF, which in part was due to a decrease in cell viability. The other EF applied was a 46 mV/mm alternating current (AC) EF. However, the 46 mV/mm AC EF showed no major differences in alignment or differentiation, compared to control conditions. For both EF treatments, the percent of mitotic cells during the last 14 h of the experiment were statistically similar to controls. Reported here, to our knowledge, is the first evidence of adult NPC differentiation affected in an EF in vitro. Further investigation and application of EFs on stem cells is warranted to elucidate the utility of EFs to control phenotypic behavior. With progress, the use of EFs may be engineered to control differentiation and target the growth of transplanted cells in a stem cell-based therapy to treat nervous system disorders.

The aim of the study was to evaluate the activity of decitabine, our preliminary experience with decitabine in patients with a hypomethylating agent, in the treatment of patients with accelerated and blastic phases of CML. chronic myelogenous leukemia (CML) in transformation. Thirtyseven patients with CML in blastic (20 patients) or accelerated phases (17 patients) were treated. Their median age was 52

The continuous renewal of human epidermis is sustained by stem cells contained in the epidermal basal layer and in hair follicles 1,2 . Cultured keratinocyte stem cells, known as holoclones 3-6 , generate sheets of epithelium used to restore severe skin, mucosal and corneal defects . Mutations in genes encoding the basement membrane component laminin 5 (LAM5) cause junctional epidermolysis bullosa (JEB), a devastating and often fatal skin adhesion disorder 10 . Epidermal stem cells from an adult patient affected by LAM5-b3-deficient JEB were transduced with a retroviral vector expressing LAMB3 cDNA (encoding LAM5-b3), and used to prepare genetically corrected cultured epidermal grafts. Nine grafts were transplanted onto surgically prepared regions of the patient's legs. Engraftment was complete after 8 d. Synthesis and proper assembly of normal levels of functional LAM5 were observed, together with the development of a firmly adherent epidermis that remained stable for the duration of the follow-up (1 year) in the absence of blisters, infections, inflammation or immune response. Retroviral integration site analysis indicated that the regenerated epidermis is maintained by a defined repertoire of transduced stem cells. These data show that ex vivo gene therapy of JEB is feasible and leads to full functional correction of the disease.

AML patients (total 129; median age ¼ 50 years; range 16-72) in first CR received BU and melphalan (BU/Mel) as conditioning regimen before auto-SCT. In all, 82 patients (63.6%) received PBSCs and 47 patients (36.4%) received BM cells. The distribution of cytogenetic categories was conventionally defined as favorable (15.5%), intermediate (60.1%) and unfavorable (24.3%). With a median followup of 31 months, the 8-year projected OS and disease-free survival (DFS) was 62 and 56% for the whole population, respectively. The relapse rate was 46% and the non-relapse mortality was 4.65%. Although PBSC transplantation led to a faster hematological recovery than BM transplantation, in univariate analysis the stem cell source, cytogenetics and different BU formulations did not significantly affect OS and DFS, whereas age and the number of postremission chemotherapy cycles did have a significant effect on the clinical outcome. Multivariate analysis identified age o55 years as the only important independent predictor for OS and DFS. Our data suggest that BU/Mel, being associated with a low toxicity profile (mainly mucositis) and mortality, is an effective conditioning regimen even for high-risk AML patients in first CR undergoing auto-SCT.

Myogenesis involves the determination of progenitor cells to myoblasts, their fusion to yield multinuclear myotubes, and the maturation of myotubes to muscle fibres. This development is reflected in a time pattern of gene expression, e.g. of genes coding for desmin, the myogenic factors myogenin and myoD, the acetylcholine receptor α-subunit and the muscular chloride channel ClC-1. We attempted to improve yields and myogenic differentiation in culture by using three-dimensional microcarrier systems. Out of a variety of carriers tested in stationary cultures, collagen-coated dextran Cytodex3 beads proved optimal for the proliferation and differentiation of the murine myogenic cell line C2C12. With C2C12 myoblasts in stationary and stirred systems (Spinner-and SuperSpinner flasks), surface adherence, differentiation into myotubes and expression of musclespecific mRNAs on Cytodex3 beads were the same as in conventional cultures. Other carriers tested (DEAE cellulose, glass, plastic, cellulose, polyester) did not support growth and differentiation of C2C12 cells. The secondary mouse myogenic stem cells M12 and M2.7-MDX proliferated and differentiated well in stationary Cyto-dex3 cultures, but no differentiation occurred in Spinner flasks. As indicated by light and scanning electron microscopy, C2C12 myotubes formed not only on but also in between Cytodex beads. The secondary cell lines may succumb to shear forces under these conditions.

Cryopreservation currently is the only method for long-term preservation of cellular viability and function for uses in cellular therapies. Characterizing the cryobiological response of a cell type is essential in the approach to designing and optimizing cryopreservation protocols. For cells used in therapies, there is significant interest in designing cryopreservation protocols that do not rely on dimethyl sulfoxide (Me 2 SO) as a cryoprotectant, since this cryoprotectant has been shown to have adverse effects on hematopoietic stem cell (HSC) transplant patients. This study characterized the cryobiological responses of the human erythroleukemic stem cell line TF-1, as a model for HSC. We measured the osmotic parameters of TF-1 cells, including the osmotically-inactive fraction, temperature-dependent membrane hydraulic conductivity and the membrane permeability to 1 M Me 2 SO. A two-step freezing procedure (interrupted rapid cooling with hold time) and a graded freezing procedure (interrupted slow cooling without hold time) were used to characterize TF-1 cell recovery during various phases of the cooling process. One outcome of these experiments was high recovery of TF-1 cells cryopreserved in the absence of traditional cryoprotectants. The results of this study of the cryobiology of TF-1 cells will be critical for future understanding of the cryobiology of HSC, and to the design of cryopreservation protocols with specific design criteria for applications in cellular therapies.

La peau et la cornée sont deux tissus de revêtement constitués d'un épithélium fermement ancré à un tissu conjonctif, le derme pour la peau et le stroma pour la cornée. Les cellules souches de la peau ont pu être amplifiées grâce à la technique de Rheinwald et Green en 1975 et utilisées dès 1981 sous forme de feuillets épidermiques pour le traitement des grands brûlés. Plus tard, cette technique de culture a été reprise pour amplifier les cellules épithéliales limbiques. La couche basale de l'épithélium limbique se situe dans la zone transitionnelle entre la cornée et la conjonctive et contient les cellules souches de l'épithélium cornéen [J Cell Biol 1 (1986) 49-52 et Cell 57 (1989) 201-209] appelées cellules souches limbiques (CSL). Elles assurent le renouvellement de l'épithélium cornéen en générant des cellules d'amplifications transitoires qui migrent de façon centripète à partir de la couche basale limbique vers la couche basale de la cornée. Le génie tissulaire permet de reconstruire des tissus en trois dimensions (3D), associant l'épithélium à son tissu conjonctif sous-jacent. Pour reconstruire le tissu conjonctif, notre modèle associe des cellules et un polymère biodégradable et naturel à base de collagène. Ce substrat poreux sert d'échafaudage à la culture de fibroblastes pour donner un derme/ stroma équivalent vivant, qui secondairement épithélialisé aboutit à une peau/hémicornée reconstruite. Nous présentons ici : la reconstruction des épithélia dans les pathologies de surface de la peau et de la cornée et le développement de nos modèles tridimensionnels de peau et de cornées à base de collagène-GAG-chitosane et leurs applications.

Objectives To evaluate cerebrospinal fluid (CSF) of preterm patients with hydrocephalus for neural progenitors. Study design This report describes a prospective study of CSF obtained from preterm infants, either with progressive posthemorrhagic hydrocephalus (PPHH) or without known intercranial pathology. Cells recovered by centrifugation were analyzed by reverse transcriptase-polymerase chain reaction or by immunocytometry. Alternatively, cells were cultured by using methods permissive to neural progenitor growth and analyzed by immunocytochemistry and Western blotting.

Umbilical cord blood (UCB) contains a high number of primitive progenitor cells, allowing UCB to be used as a source of hematopoietic progenitors for clinical transplantation. However the rate of UCB CD34 z stem cells graft is low. Mesenchymal stem cells (MSCs) have been implicated in playing an important role in hematopoietic stem cell engraftment.

The concept of tissue and cell guidance is rapidly evolving as more information regarding the effect of the microenvironment on cellular function and tissue morphogenesis become available. These disclosures have lead to a tremendous advancement in the design of a new generation of multifunctional biomaterials able to mimic the molecular regulatory characteristics and the three-dimensional architecture of the native extracellular matrix. Micro-and nano-structured scaffolds able to sequester and deliver in a highly specific manner biomolecular moieties have already been proved to be effective in bone repairing, in guiding functional angiogenesis and in controlling stem cell differentiation. Although these platforms represent a first attempt to mimic the complex temporal and spatial microenvironment presented in vivo, an increased symbiosis of material engineering, drug delivery technology and cell and molecular biology may ultimately lead to biomaterials that encode the necessary signals to guide and control developmental process in tissue-and organ-specific differentiation and morphogenesis.

The chemokine receptor CXCR4 belongs to the large superfamily of G-protein-coupled receptors, and is directly involved in a number of biological processes including organogenesis, hematopoiesis, and immunity. Recent evidence has highlighted the role of CXCR4 in a variety of diseases including cancer and WHIM syndrome. Expression of CXCR4 in cancer metastasis appears to be due to dysregulation of the receptor leading to enhanced signaling. CXCR4 was also found to be a prognostic marker in various types of cancer including leukemia and breast cancer. These observations reveal that CXCR4 is an important molecule involved in several aspects of cancer progression. The SDF-1-CXCR4 axis is also involved in normal stem cell homing. Interestingly, cancer stem cells also express CXCR4 suggesting that the SDF-1-CXCR4 axis directs their trafficking/metastasis to organs that highly express SDF-1 such as the lymph nodes, lungs, liver, and bones. Here, we review what is currently known regarding the regulation of CXCR4 and how dysregulation contributes to disease progression. The Chemokine Receptor CXCR4 and Cancer The human chemokine system currently includes more than 40 chemokines and 18 chemokine receptors (Table 1). Chemokine receptors are defined by their ability to induce directional migration of cells toward a gradient of a chemotactic cytokine (chemotaxis). Chemokine receptors belong to a family of 7 transmembrane domain, G-protein-coupled cell surface receptors (GPCR) and the ligands are classified into four groups (CXC, CC, C, and CX 3 C) based on the position of the first two cysteines [1, 2]. Chemokine receptors are present on many different cell types. Initially, these receptors were identified on

The aim of this study was to evaluate the osteogenic potential and the vascularization of embroidered, tissue engineered, and cell-seeded 3D poly(3)hydroxybutyrate (PHB) scaffolds in nude rats. Collagen I (coll I)- and collagen I/chondroitin sulfate (coll I/CS)-coated PHB scaffolds were seeded with human mesenchymal stem cells (hMSCs). Proliferation and differentiation were characterized by different biochemical assays in vitro. For animal experiments, the cells were cultivated on coll I- or coll I/CS-coated scaffolds and either expanded or osteogenically differentiated. Scaffolds were piled up to create a 3D scaffold pad and implanted subcutaneously into nude rats. In vitro hMSC showed proliferation and differentiation on PHB scaffolds. Alkaline phosphatase (ALP) and calcium increased in the differentiation medium and in the presence of coll I/CS. In vivo blood vessels were found in the scaffold-stack. Histological/immunohistological analyses of explanted scaffolds showed osteogenic markers such as osteopontin, osteonectin, and coll I around the PHB fibers. Coll I/CS-coated scaffolds with expanded hMSC showed higher values of ALP and calcium than the other combinations. Embroidered PHB scaffolds, coated with extracellular matrix components, provided an adequate environment and, therefore, a template for hMSC which could be differentiated in osteogenic direction. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res, 2010

Bone marrow sinusoidal endothelial cells have a specific function as a site of transmigration of hematopoietic stem and progenitor cells and mature blood cells between bone marrow and blood stream. However, the specific characteristics of bone marrow sinusoidal endothelial cells are still largely unclear. We here report that these cells express stabilin-1 and stabilin-2, which in liver sinusoidal endothelial cells have been identified as endocytic scavenger receptors for several ligands, including SPARC and hyaluronan. We show here that intravenously injected formaldehyde-treated serum albumin, advanced glycation end-products, and collagen I a-chains were taken up by bone marrow sinusoidal endothelial cells, showing that these cells have a scavenging function and thereby may modulate bone marrow vascular stem cell niches. Importantly, we show hyaluronan mediated adhesion of hematopoietic stem and progenitor cells to stabilin-2-transfected cells, suggesting that stabilin-2 contributes to adhesion and homing of circulating stem and progenitor cells to bone marrow.

The International Stem Cell Initiative characterized 59 human embryonic stem cell lines from 17 laboratories worldwide. Despite diverse genotypes and different techniques used for derivation and maintenance, all lines exhibited similar expression patterns for several markers of human embryonic stem cells. They expressed the glycolipid antigens SSEA3 and SSEA4, the keratan sulfate antigens TRA-1-60, TRA-1-81, GCTM2 and GCT343, and the protein antigens CD9, Thy1 (also known as CD90), tissue-nonspecific alkaline phosphatase and class 1 HLA, as well as the strongly developmentally regulated genes NANOG, POU5F1 (formerly known as OCT4), TDGF1, DNMT3B, GABRB3 and GDF3. Nevertheless, the lines were not identical: differences in expression of several lineage markers were evident, and several imprinted genes showed generally similar allelespecific expression patterns, but some gene-dependent variation was observed. Also, some female lines expressed readily detectable levels of XIST whereas others did not. No significant contamination of the lines with mycoplasma, bacteria or cytopathic viruses was detected.