Journal of Stem Cells最新文献

Hematopoietic stem cells (HSC) are multipotent cells that produce the various lineages of blood and HSC transplantations (HSCT) are widely used to reconstitute damaged bone marrow (BM). Over time, HSCT has evolved for the treatment of non-blood diseases as well, brain in particular. However, HSCT required total myeloablation through irradiation and/or chemotherapy for the treatment of BM-related diseases, and HSCs are difficult to safely deliver in large amounts into the brain. In blood disorders, for a minimal myelosuppression to be sufficient and allow donor cells to engraft, it is necessary to determine the minimal percentage of normal BM cells needed to achieve phenotypic correction. Recent studies on animal models of ?-thalassemia and sickle cell disease (SCD), through Competitive Repopulation Assay (CRA) following lethal irradiation of recipients, demonstrated that an average of 25% normal BM cells allows the production of enough normal red blood cells to significantly correct the ?-thalassemia and SCD phenotypes, at the levels of BM, blood, histology, and survival, with normal donor cells contributing to 50-60% of peripheral red blood cells. Further assays using mild myelosuppression showed that long term sustained phenotypic correction can be obtained for both diseases through a novel transplantation strategy based on modulating four parameters: dose of irradiation/myelosuppression, number of transplanted cells, timing of cell injections, and number of cell doses. Through a minimal dose of irradiation of 1Gy (100 Rads) or 2Gy, two injections of BM cells within the first 24h after myelosuppression resulted in engraftment in 100% of mice and a sustained therapeutic mixed chimerism in ?-thalassemia, while three to four injections were needed to achieve a similar outcome in SCD. Following the success of these trials, we modified this novel HSCT strategy and applied it to determine whether we can protect mice from lethal stroke induced through the Middle Cerebral Artery Occlusion (MCAO). Ischemia/reperfusion resulted in a major infarct that propagated over time to encompass ~70% of the affected hemisphere. When two doses of HSCs were injected at 2h and 24h after the reperfusion, 40% of mice survived, visible neurological defects disappeared, and the infarct size was reduced by two to four fold. Histological examination of brains in surviving mice revealed very few donor cells in the recipient brains, decreased total neurons count and increased glial cell numbers. These data suggest that the neuro-protection was not dependent on cell-supplementation, but rather the protection is manifested likely through growth factor secretion. Combined, these studies create a novel HSCT approach that has proved efficient for the treatment of various disorders. A "window of opportunity" exists for each disease where the donor cells should be administered, and multiple injections of donor HSCs can rescue diseases that would otherwise not be treatable. We

Bird embryogenesis takes place in a relatively protected environment that can be manipulated especially well in domestic fowl (chickens) where incubation has long been a commercial process. The embryonic developmental process has been shown to begin in the oviduct such that the embryo has attained either the blastodermal and/or gastrulation stage of development at oviposition. Bird embryos can be affected by "maternal effects," and by environmental conditions during the pre-incubation and incubation periods. "Maternal effects" has been described as an evolutionary mechanism that has provided the mother, by hormonal deposition into the yolk, with the potential to proactively influence the development of her progeny by exposing them to her particular hormonal pattern in such a manner as to influence their ability to cope with the expected wide range of environmental conditions that may occur post-hatching. Another important aspect of "maternal effects" is the effect of the maternal nutrient intake on progeny traits. From a commercial broiler chicken production perspective, it has been established that greater cumulative nutrient intake by the hen during her pullet rearing phase prior to photostimulation resulted in faster growing broiler progeny. Generally, maternal effects on progeny, which have both a genetic and an environmental component represented by yolk hormones deposition and embryo nutrient utilization, have an important effect on the development of a wide range of progeny traits. Furthermore, commercial embryo development during pre-incubation storage and incubation, as well as during incubation per se has been shown to largely depend upon temperature, while other environmental factors that include egg position during storage, and the amount of H2O and CO2 lost by the egg and the subsequent effect on albumen pH and height during storage have become important environmental factors to be considered for successful embryogenesis under commercial conditions. Manipulating environmental temperature during the period of egg storage, during the intermediate pre-incubation period, and incubation period per se has been found to significantly affect embryo development, hatching progress, chick quality at hatching, and chick development post-hatching. These temperature manipulations have also been shown to affect the acquisition of thermotolerance to subsequent post-hatching thermal challenge. This chapter will focus on: a. "maternal effects" on embryo and post-hatching development; b. environmental effects during the post-ovipositional period of egg storage, the intermediate pre-incubation period, and incubation period per se on chick embryogenesis and subsequent post-hatching growth and development; and c. effects of temperature manipulations during the pre-incubation and incubation periods on acquisition of thermotolerance and development of secondary sexual characteristics in broiler chickens.

Stem cells can be defined as cells that have the capacity to self-renew and the ability to generate differentiated progeny or multiple cell lineages. True stem cells can turn into any type of cells, while progenitor cells are more or less committed to becoming cell types of a particular tissue. Human corneal epithelial stem cells (CESCs) represent a great example and model of adult stem or progenitor cells. Human CESCs have been identified to locate in the basal epithelial layer of the limbus, and thus also referred as to limbal stem cells. We would like to use the both terms, stem and progenitor cells in this chapter based on previous use in the literature for more than two decades. Although the CESCs have been identified to reside at the limbus and many stem cell markers have been proposed, there is no consensus to date regarding the definitive markers for CESCs, and identification and isolation of these cells are still challenging. Based on evaluation of a variety of proposed markers, we have characterized that the CESCs located in the basal layer of human limbal epithelium are small primitive cells expressing three patterns of molecular markers, which represent a unique phenotype of putative corneal epithelial stem or progenitor cells. Based on adult stem cell criteria and the putative limbal stem cell phenotype, our group has attempted to enrich for human CESCs through novel approaches including cell-sizing, adhering to extracellular matrix collagen type IV, and cell sorting for side population or for expression of ABCG2 or connexin 43 cell surface markers. The 5 clonogenic populations isolated from limbal epithelium and its cultures by different methods show the properties that are characteristics of adult stem/progenitor cells: 1) relatively undifferentiated, 2) high proliferative potential, 3) self-renewal. Expansion and cultivation of corneal epithelial progenitor cells have been achieved using different methods, such as limbal tissue explant culture, and limbal epithelial cell suspension co-culture with mouse 3T3 fibroblast feed layer. To avoid the use of xeno-components, two cell lines of commercial human fibroblasts have been identified that support human corneal epithelial regeneration, and have potential use in replacing mouse 3T3 cells for corneal tissue bioengineering. The concept of CESCs has formed the basis for identifying a class of blinding diseases that display features of corneal epithelial stem cell deficiency or limbal stem cell deficiency (LSCD), where the limbal epithelium is damaged. LSCD is characterized by persistent or recurrent epithelial defects, ulceration, corneal vascularization, chronic inflammation, scarring, and conjunctivalization (conjunctival epithelial ingrowth). Only transplantation of CESCs can restore vision. Due to an increasing shortage of corneal donors, corneal tissue engineering is becoming an important discipline that holds great promise for corneal reconstruction. CESCs and optical substr

Endothelial progenitor cells (EPC) are mobilized after myocardial infarction (MI) from the bone marrow to injured sites of the heart where they participate in cardiac repair by revascularization of ischemic tissues. Endothelial progenitor cells have been actively studied, but their exact phenotype and regenerative properties are still controversial. Small trials with progenitor cells of different origins showed modest clinical benefits. It is assumed that a better understanding of the biology of EPC will contribute to improve their therapeutic potential. MicroRNAs (miRNAs) are small single-stranded non-coding RNAs that modulate gene expression by interacting post transcriptionally with protein-coding RNAs. MicroRNAs regulate multiple biological processes involved in cardiac development and disease. While many studies addressed the role of miRNAs in cardiac cells, less is known of the effect of miRNAs in EPC. Recent studies showed that miRNAs indeed regulate the biology of EPC. Since novel technologies to enhance or blunt the functions of miRNAs have been recently developed, it is conceivable that miRNAs may become promising new therapeutic tools. This article will review the recent advances in the knowledge of the effects of miRNAs in EPC and will discuss how miRNAs could be manipulated to improve the regenerative capacities of EPC in the diseased heart.

Aim: Evaluation of safety in using unmatched human allogeneic umbilical cord blood cells for therapeutic use in individuals with non-haematopoietic degenerative conditions.

Background: The historical data and several recent immunological arguments suggest the therapeutic use of allogeneic Cord Blood Mononuclear Cells (CBMNCs), as these cells do not elicit immune response. Customarily, HLA matched cord blood MNCs are used along with prolonged immunosuppression in treatment of haematological conditions. Lately, unmatched CBMNCs are widely used in case of unavailability of HLA matched cord blood. There have been suggestions for using unmatched allogeneic cord blood MNCs for degenerative conditions without an immunoconditioning regimen.

Method: 49 patients with non-haematopoietic degenerative conditions were treated with HLA-unmatched allogeneic hUCB MNCs. Intrathecal/I.V injections (1-2 million cells/kg body weight) were given. Clinical, biochemical and haematological adverse events were evaluated.

Results: The haematological and biochemical parameters showed no major deviation from the normal. Clinically, no acute adverse effects or GVHD were observed with the used dosage.

Conclusion: This study supports/suggests clinical safety in therapeutic medical use of unmatched allogeneic CBMNCs when used at low dosage in non-haematopoietic degenerative conditions.

Background: Umbilical Mesenchymal Stem Cells possess immunoregulatory capacities that have been permissive to allogenic transplantation. Recent animal studies have demonstrated histologically that bone marrow- derived mesenchymal stem cells (MSCs) may enhance the regeneration of periodontal defects in dogs by differentiating MSCs into cementoblasts, osteoblasts and periodontal fibroblasts.

Aim: To compare the clinical efficacy between stem cells in combination with PLA/PGA membrane and subepithelial connective tissue graft (SCTG) in the treatment of multiple gingival recession defects.

Methods: Twenty four patients aged between 20 to 33 years (mean age 27.41 ± 1.06 years) with multiple gingival recession defects on labial or buccal surface of the teeth in the aesthetic zone either in maxilla or mandible were treated. The test group was treated using stem cells cultured on bioresorbable PLA/PGA membrane, while control group was treated using SCTG. Following parameters were assessed, Plaque Index (PI),Gingival Bleeding Point Index (GBI), Relative gingival margin level (RGML), Relative attachment level (RAL) and Probing pocket depth (PPD) Results: In the test group, mean percent defect coverage was 72.43 ± 13.55 % and the predictability was 41.17% for root coverage i.e 14 of 34 defects, while in the control group, mean percent defect coverage was 82.06 ± 10.99 % and the predictability was 50 % for root coverage i.e 15 of 30 defects.

Conclusion: Stem cells in combination with bioresorbable PLA/PGA membrane was effective for root coverage resulted in a significant reduction in gingival recession, greater gain in CAL and WKG. Stem cells in combination with bioresorbable PLA/PGA membrane resulted in significantly higher CAL gain than SCTG.

The concept of extramedullary hematopoiesis for production of organ-specific antigen presenting cells has importance in immunity in terms of the compartmentalisation of the immune response in different tissue sites. A new and distinct dendritic-like antigen presenting cell subtype is described which is dependent on the spleen microenvironment for development. Cells arise by a unique developmental pathway distinct from other dendritic cells (DC). In particular, a self-renewing progenitor of these cells has been identified in spleen upstream of the earliest DC progenitor currently identified in bone marrow. This progenitor depends on the splenic microenvironment for maintenance and proliferation, adding further support for spleen as a site for hematopoiesis.

Unlabelled: Wound healing is an inherent property of injured tissue or a group of cells. The healing front is always developed by new cells which are progenitor of differentiated parental cells. In cancer tissues we aim to study the healing front and observed an enriched population of stem cell like properties in the developing front when compared to the other areas of the cell matrix.

Method: In vitro scratch assays with special focus on stem cell expression was used to analyze metastatic potential of the tumor cell, epithelial to mesenchymal transition and rate of cell migration to get an insight into the genes and the proteins getting expressed at the developing front. In this protocol we describe a fluorescence dependent method to document stem cell like enrichment at the developing front of a given wound in drug treated and untreated control cells under the same culture conditions in a time lag manner. We have tried to compare the rate of cell migration and the expression levels of stem cell markers between the treated and untreated cells.

Results: CD44 being a cell surface protein and being involved in cell migration and proliferation, higher intensity of CD44 was observed at the developing front with increasing time. The rate of cell migration differed with different treatments and so did the CD44 expression with expression being higher in 0.6mM concentration of bleomycin when compared to 0.4mM. Similar expression was observed for ALDH1 stem cell marker. This particular technique can not only be used for studying expression of CSC markers (like CD44, ALDH1) but also in assaying the expression profile of several proteins involved in cellular processes like EMT (Epithelial to Mesenchymal Transition), cell migration, tumorigeneisis and rate of proliferation.

Conclusion: Would healing is an integral property of solid tissues and in solid tumors properties of solid tissue wound are important characteristics of tumor development. Therefore combining the properties of stem cell like enrichment in the development front would be an important and fast assay to study migratory and metastatic properties of an invitro culture.

The time lapse photography is not a new method for assessing the dynamics of early embryo development in vitro. It has been used many times in the past for studying cleavages and blastulation of embryos of various animal species. However, this technique became available for routine use in an human in vitro fertilization (IVF) programme only a couple years ago and it becomes more and more popular today. The new time lapse systems are using modified microscopes which are positioned within the incubators. The observation of embryos does not need the opening of incubators. By sequential photographing of each embryo separately with camera of low intensity illumination, more than 1400 pictures of embryo are made. All these pictures are collected together and transformed into a short movie with software. This system offers the observation of dynamics of embryo development. The studies, which have used a time lapse technique for studying embryo development, revealed that the timing between different events can be used for predicting its developmental potential. In this paper the advantages and drawbacks of time lapse photography is precisely described. An overview through the published papers analyzing the dynamics of human embryo development from the zygote toward blastocyst is done and new timing parameters for grading zygotes, early embryos and blastocysts are analyzed.

As described in this book, the interaction between the immune system and the brain can affect multiple cerebral functions, such as: neural remodeling, synaptic plasticity or neurotransmitter releasing. Neurogenic niches are not the exception, in fact, pro-inflammatory cytokines and chemokines exert a strong regulation in neural stem cells (NSCs) of the ventricular-subventricular zone (V-SVZ) by interacting with cell membrane receptors and activating multiple downstream pathways. These neuro-immune interactions modulate quiescence, cell adhesion, migration, self-renewal, differentiation, cytoskeletal rearrangement, and cell survival. In this chapter, we describe the cellular composition and cytoarchitecture of the main neurogenic niche in the adult mammalian brain: the V-SVZ. We also discuss the current evidence indicating that many immunological molecules can control the function of this neurogenic niche in the adult brain under both physiological and pathological conditions.