Commercial human 3D corneal epithelial equivalents for modeling epithelial infection in herpes keratitis

Herpes stromal keratitis is the leading cause of infectious blindness in the western world. Infection by HSV1 is most common, but VZV and hCMV also infect the cornea. Multiple models of HSV1 corneal infection exist, but none for VZV and hCMV because of their host specificity. Here, we used commercially available 3D human corneal epithelial equivalents (HCEE) to study infection by these herpesviruses. HCEE was infected by HSV-1 and hCMV without requiring scarification and resulted in spreading infections. Spread of HSV-1 infection was rapid, while that of hCMV was slow. In contrast, infections with VZV required damage to the HCEE and did not spread. Acyclovir dramatically reduced replication of HSV-1 in this model. We conclude that highly quality-controlled, readily available HCEE is a useful model to study human-restricted herpesvirus infection of the human corneal epithelium and for screening of antiviral drugs for treating HSK in an 3D model system.

Studies of Infection and Experimental Reactivation by Recombinant VZV with Mutations in Virally-Encoded Small Non-Coding RNA

Locked-nucleotide analog antagonists (LNAA) to four varicella zoster virus small non-coding RNA (VZVsncRNA 10-13) derived from the mRNA of the open reading frame (ORF) 61 gene individually reduce VZV replication in epithelial cells and fibroblasts. To study the potential roles VZVsncRNA 10-13 have in neuronal infection we generated two recombinant VZV; one in which 8 nucleotides were changed in VZVsncRNA10 without altering the encoded residues of ORF61 (VZVsnc10MUT) and a second containing a 12-nucleotide deletion of the sequence common to VZVsncRNA12 and 13, located in the ORF61 mRNA leader sequence (VZVsnc12-13DEL). Both were developed from a VZV BAC with a green fluorescent protein (GFP) reporter fused to the N terminal of the capsid protein encoded by ORF23. The growth of both mutant VZV in epithelial cells and fibroblasts was similar to that of the parental recombinant virus. Both mutants established productive infections and experimental latency in neurons derived from human embryonic stem cells (hESC). However, neurons that were latently infected with both VZV mutant viruses showed impaired ability to reactivate when given stimuli that successfully reactivated the parental virus. These results suggest that these VZVsncRNA may have a role in VZV latency maintenance and/or reactivation. The extension of these studies and confirmation of such roles could potentially inform the development of a non-reactivating, live VZV vaccine.

Antiviral Targeting of Varicella Zoster Virus Replication and Neuronal Reactivation Using CRISPR/Cas9 Cleavage of the Duplicated Open Reading Frames 62/71

Varicella Zoster Virus (VZV) causes Herpes Zoster (HZ), a common debilitating and complicated disease affecting up to a third of unvaccinated populations. Novel antiviral treatments for VZV reactivation and HZ are still in need. Here, we evaluated the potential of targeting the replicating and reactivating VZV genome using Clustered Regularly Interspaced Short Palindromic Repeat-Cas9 nucleases (CRISPR/Cas9) delivered by adeno-associated virus (AAV) vectors. After AAV serotype and guide RNA (gRNA) optimization, we report that a single treatment with AAV2-expressing Staphylococcus aureus CRISPR/Cas9 (saCas9) with gRNA to the duplicated and essential VZV genes ORF62/71 (AAV2-62gRsaCas9) greatly reduced VZV progeny yield and cell-to-cell spread in representative epithelial cells and in lytically infected human embryonic stem cell (hESC)-derived neurons. In contrast, AAV2-62gRsaCas9 did not reduce the replication of a recombinant virus mutated in the ORF62 targeted sequence, establishing that antiviral effects were a consequence of VZV-genome targeting. Delivery to latently infected and reactivation-induced neuron cultures also greatly reduced infectious-virus production. These results demonstrate the potential of AAV-delivered genome editors to limit VZV productive replication in epithelial cells, infected human neurons, and upon reactivation. The approach could be developed into a strategy for the treatment of VZV disease and virus spread in HZ.

Varicella Zoster Virus Neuronal Latency and Reactivation Modeled in Vitro

Latency and reactivation in neurons are critical aspects of VZV pathogenesis that have historically been difficult to investigate. Viral genomes are retained in many human ganglia after the primary infection, varicella; and about one-third of the naturally infected VZV seropositive population reactivates latent virus, which most often clinically manifests as herpes zoster (HZ or Shingles). HZ is frequently complicated by acute and chronic debilitating pain for which there remains a need for more effective treatment options. Understanding of the latent state is likely to be essential in the design of strategies to reduce reactivation. Experimentally addressing VZV latency has been difficult because of the strict human species specificity of VZV and the fact that until recently, experimental reactivation had not been achieved. We do not yet know the neuron subtypes that harbor latent genomes, whether all can potentially reactivate, what the drivers of VZV reactivation are, and how immunity interplays with the latent state to control reactivation. However, recent advances have enabled a picture of VZV latency to start to emerge. The first is the ability to detect the latent viral genome and its expression in human ganglionic tissues with extraordinary sensitivity. The second, the subject of this chapter, is the development of in vitro human neuron systems permitting the modeling of latent states that can be experimentally reactivated. This review will summarize recent advances of in vitro models of neuronal VZV latency and reactivation, the limitations of the current systems, and discuss outstanding questions and future directions regarding these processes using these and yet to be developed models. Results obtained from the in vitro models to date will also be discussed in light of the recent data gleaned from studies of VZV latency and gene expression learned from human cadaver ganglia, especially the discovery of VZV latency transcripts that seem to parallel the long-studied latency-associated transcripts of other neurotropic alphaherpesviruses.

Locked-nucleotide antagonists to varicella zoster virus small non-coding RNA block viral growth and have potential as an anti-viral therapy

Herpes zoster (HZ) remains a significant health burden with millions of cases in North America and Europe annually. HZ is frequently followed by long-term pain or post-herpetic neuralgia (PHN). Although effective vaccines for HZ are available, currently used nucleotide analogues often have limited effectiveness against HZ and especially PHN, so there remains a need for additional antiviral therapies for HZ. We recently identified a population of small non-coding RNA (sncRNA) encoded by Varicella Zoster Virus (VZV) and showed that single locked-nucleic acid antagonists (LNAA) to some sncRNA can modulate VZV replication in cell culture. In this work, we explored the antiviral effects of combinations of LNAA oligonucleotides targeting VZVsncRNA. Combinations of LNAA targeting three VZVsncRNA encoded in and near a critical viral regulatory gene were additive, achieving 96 % reduction in virus growth in a cell line. VZV growth was also inhibited by more than 90 % in primary human skin fibroblast cultures by individual and combinations of LNAA to VZVsncRNA. The inhibition by VZVsncRNA was specific and not a consequence of innate immune responses since LNAA to a different VZVsncRNA enhanced VZV growth. Targeted VZVsncRNA lack homologous sequences in the human transcriptome suggesting that LNAA to them would have reduced cytotoxicity if used as therapeutics. These results support further development of oligonucleotides targeting VZVsncRNA as a novel treatment for HZ.

Bioinformatically-predicted varicella zoster virus small non-coding RNAs are expressed in lytically-infected epithelial cells and neurons

Most herpesviruses use both host and viral small non-coding RNAs (sncRNA), especially microRNA, to modulate infection. Bioinformatic analyses of NGS data obtained from Varicella Zoster virus (VZV)-infected cells predicted 24 VZVsncRNA, seven of which were confirmed to be expressed in infected fibroblasts and neurons using stem-loop quantitative reverse transcription PCR (SL-PCR). We here assayed for the expression of all 24 of the bioinformatically predicted VZVsncRNA in cells productively infected by VZV using SL-PCR. 23 of the 24 predicted sequences were detected in VZV-infected ARPE19 cells and 19 of the 24 sequences in infected human neurons generated by two methods from embryonic stem cells. We also show that blocking one of two newly-tested VZV-encoded sncRNA using locked nucleotide antagonists significantly increased viral replication. These findings suggest that further study of VZV encoded sncRNA could elucidate an additional level of regulation of the life cycle of this pathogenic human herpesvirus.

Modeling Varicella Zoster Virus Persistence and Reactivation - Closer to Resolving a Perplexing Persistent State

The latent state of the human herpesvirus varicella zoster virus (VZV) has remained enigmatic and controversial. While it is well substantiated that VZV persistence is established in neurons after the primary infection (varicella or chickenpox), we know little of the types of neurons harboring latent virus genomes, if all can potentially reactivate, what exactly drives the reactivation process, and the role of immunity in the control of latency. Viral gene expression during latency has been particularly difficult to resolve, although very recent advances indicate that it is more restrictive than was once thought. We do not yet understand how genes expressed in latency function in the maintenance and reactivation processes. Model systems of latency are needed to pursue these questions. This has been especially challenging for VZV because the development of in vivo models of VZV infection has proven difficult. Given that up to one third of the population will clinically reactivate VZV to develop herpes zoster (shingles) and suffer from its common long term problematic sequelae, there is still a need for both in vivo and in vitro model systems. This review will summarize the evolution of models of VZV persistence and address insights that have arisen from the establishment of new in vitro human neuron culture systems that not only harbor a latent state, but permit experimental reactivation and renewed virus production. These models will be discussed in light of the recent data gleaned from the study of VZV latency in human cadaver ganglia.

Axonal PPARγ promotes neuronal regeneration after injury

PPARγ is a ligand-activated nuclear receptor best known for its involvement in adipogenesis and glucose homeostasis. PPARγ activity has also been associated with neuroprotection in different neurological disorders, but the mechanisms involved in PPARγ effects in the nervous system are still unknown. Here we describe a new functional role for PPARγ in neuronal responses to injury. We found both PPAR transcripts and protein within sensory axons and observed an increase in PPARγ protein levels after sciatic nerve crush. This was correlated with increased retrograde transport of PPARγ after injury, increased association of PPARγ with the molecular motor dynein, and increased nuclear accumulation of PPARγ in cell bodies of sensory neurons. Furthermore, PPARγ antagonists attenuated the response of sensory neurons to sciatic nerve injury, and inhibited axonal growth of both sensory and cortical neurons in culture. Thus, axonal PPARγ is involved in neuronal injury responses required for axonal regeneration. Since PPARγ is a major molecular target of the thiazolidinedione (TZD) class of drugs used in the treatment of type II diabetes, several pharmaceutical agents with acceptable safety profiles in humans are available. Our findings provide motivation and rationale for the evaluation of such agents for efficacy in central and peripheral nerve injuries.

Direct transfer of viral and cellular proteins from varicella-zoster virus-infected non-neuronal cells to human axons

Varicella Zoster Virus (VZV), the alphaherpesvirus that causes varicella upon primary infection and Herpes zoster (shingles) following reactivation in latently infected neurons, is known to be fusogenic. It forms polynuclear syncytia in culture, in varicella skin lesions and in infected fetal human ganglia xenografted to mice. After axonal infection using VZV expressing green fluorescent protein (GFP) in compartmentalized microfluidic cultures there is diffuse filling of axons with GFP as well as punctate fluorescence corresponding to capsids. Use of viruses with fluorescent fusions to VZV proteins reveals that both proteins encoded by VZV genes and those of the infecting cell are transferred in bulk from infecting non-neuronal cells to axons. Similar transfer of protein to axons was observed following cell associated HSV1 infection. Fluorescence recovery after photobleaching (FRAP) experiments provide evidence that this transfer is by diffusion of proteins from the infecting cells into axons. Time-lapse movies and immunocytochemical experiments in co-cultures demonstrate that non-neuronal cells fuse with neuronal somata and proteins from both cell types are present in the syncytia formed. The fusogenic nature of VZV therefore may enable not only conventional entry of virions and capsids into axonal endings in the skin by classical entry mechanisms, but also by cytoplasmic fusion that permits viral protein transfer to neurons in bulk.

Ascites-derived pancreatic ductal adenocarcinoma primary cell cultures as a platform for personalised medicine

BACKGROUND

Challenges in developing drugs for pancreatic ductal adenocarcinoma (PDAC) include obtaining metastatic cancer tissue for research and validating biomarkers predicative for personalised therapeutic decisions. We have recently developed a novel therapeutic model for PDAC to address these challenges based on the isolation of viable PDAC cells derived from ascites fluid.

METHODS

Ascites fluid was obtained from PDAC patients undergoing palliative paracentesis. Ascites-derived PDAC primary cells were isolated, cultured and characterised in ovo and in vitro.

RESULTS

We successfully established ascites-derived primary cell cultures within 2-7 days from 92% (93 out of 101) of the ascites fluid samples obtained (from 36 different patients). Homogeneous epithelial PDAC-enriched cell cultures were identified and characterised. We observed a wide range in doubling times and migration properties among the different patient-derived cell cultures. The diverse nature of each individual patient's cell cultures was further demonstrated by differences in therapeutic susceptibility and resistance. The tumorigenicity and invasiveness of the cells were demonstrated in vivo using chicken chorioallantoic membrane grafts.

CONCLUSIONS

We have developed a unique ascites-derived PDAC primary cell culture model. This model has the potential to study signalling pathways in PDAC progression and to evaluate targeted therapies for the individual patient expeditiously, thereby supporting personalised treatment decisions.

Nocturnal noninvasive positive pressure ventilation in stable COPD: a systematic review and individual patient data meta-analysis

INTRODUCTION

The effects of nocturnal noninvasive positive pressure ventilation (NIPPV) in patients with stable chronic obstructive pulmonary disease (COPD) remain controversial.

METHODS

The Cochrane Airways group Register of Trials, MEDLINE, EMBASE and CINAHL were searched up to August 2012. Individual patient data from randomised controlled trials on NIPPV outcomes were selected for two separate meta-analyses: the first with follow-up of 3 months and the second with 12 months of follow-up. Additionally, subgroup analyses within the NIPPV group comparing IPAP levels, compliance and levels of hypercapnia on change in PaCO2 after 3 months were performed.

RESULTS

Seven trials (245 patients) were included. All studies were considered of moderate to high quality. No significant difference was found between NIPPV and control groups after 3 or 12 months of follow-up when looking at PaCO2 and PaO2, 6-minute walking distance, health-related quality-of-life, forced expiratory volume in 1 s, forced vital capacity, maximal inspiratory pressure and sleep efficiency. Significant differences in change in PaCO2 after 3 months were found for patients ventilated with IPAP levels of at least 18 cm H2O, for patients who used NIPPV for at least 5 h per night as well as for patients with baseline PaCO2 of at least 55 mm Hg when compared to patients with lower IPAP levels, poorer compliance or lower levels of hypercapnia.

DISCUSSION

At present, there is insufficient evidence to support the application of routine NIPPV in patients with stable COPD. However, higher IPAP levels, better compliance and higher baseline PaCO2 seem to improve PaCO2.

Identification of human nephron progenitors capable of generation of kidney structures and functional repair of chronic renal disease

Identification of tissue-specific renal stem/progenitor cells with nephrogenic potential is a critical step in developing cell-based therapies for renal disease. In the human kidney, stem/progenitor cells are induced into the nephrogenic pathway to form nephrons until the 34 week of gestation, and no equivalent cell types can be traced in the adult kidney. Human nephron progenitor cells (hNPCs) have yet to be isolated. Here we show that growth of human foetal kidneys in serum-free defined conditions and prospective isolation of NCAM1(+) cells selects for nephron lineage that includes the SIX2-positive cap mesenchyme cells identifying a mitotically active population with in vitro clonogenic and stem/progenitor properties. After transplantation in the chick embryo, these cells-but not differentiated counterparts-efficiently formed various nephron tubule types. hNPCs engrafted and integrated in diseased murine kidneys and treatment of renal failure in the 5/6 nephrectomy kidney injury model had beneficial effects on renal function halting disease progression. These findings constitute the first definition of an intrinsic nephron precursor population, with major potential for cell-based therapeutic strategies and modelling of kidney disease.

Reactivation of NCAM1 defines a subpopulation of human adult kidney epithelial cells with clonogenic and stem/progenitor properties

The nephron is composed of a monolayer of epithelial cells that make up its various compartments. In development, these cells begin as mesenchyme. NCAM1, abundant in the mesenchyme and early nephron lineage, ceases to express in mature kidney epithelia. We show that, once placed in culture and released from quiescence, adult human kidney epithelial cells (hKEpCs), uniformly positive for CD24/CD133, re-express NCAM1 in a specific cell subset that attains a stem/progenitor state. Immunosorted NCAM1(+) cells overexpressed early nephron progenitor markers (PAX2, SALL1, SIX2, WT1) and acquired a mesenchymal fate, indicated by high vimentim and reduced E-cadherin levels. Gene expression and microarray analysis disclosed both a proximal tubular origin of these cells and molecules regulating epithelial-mesenchymal transition. NCAM1(+) cells generated clonal progeny when cultured in the presence of fetal kidney conditioned medium, differentiated along mesenchymal lineages but retained the unique propensity to generate epithelial kidney spheres and produce epithelial renal tissue on single-cell grafting in chick CAM and mouse. Depletion of NCAM1(+) cells from hKEpCs abrogated stemness traits in vitro. Eliminating these cells during the regenerative response that follows glycerol-induced acute tubular necrosis worsened peak renal injury in vivo. Thus, higher clone-forming and developmental capacities characterize a distinct subset of adult kidney-derived cells. The ability to influence an endogenous regenerative response via NCAM1 targeting may lead to novel therapeutics for renal diseases.

Productive vs non-productive infection by cell-free varicella zoster virus of human neurons derived from embryonic stem cells is dependent upon infectious viral dose

Varicella Zoster virus (VZV) productively infects humans causing varicella upon primary infection and herpes zoster upon reactivation from latency in neurons. In vitro studies using cell-associated VZV infection have demonstrated productive VZV-infection, while a few recent studies of human neurons derived from stem cells incubated with cell-free, vaccine-derived VZV did not result in generation of infectious virus. In the present study, 90%-pure human embryonic stem cell-derived neurons were incubated with recombinant cell-free pOka-derived virus made with an improved method or VZV vaccine. We found that cell-free pOka and vOka at higher multiplicities of infection elicited productive infection in neurons followed by spread of infection, cytopathic effect and release of infectious virus into the medium. These results further validate the use of this unlimited source of human neurons for studying unexplored aspects of VZV interaction with neurons such as entry, latency and reactivation.

Simple generation of neurons from human embryonic stem cells using agarose multiwell dishes

Human embryonic stem cells (hESC) are potentially an unlimited source of neurons for study and therapy for human disease. Directed differentiation of hESC has been performed using many different methods, often via neural precursor intermediates generated from aggregates of hESC. We describe here a protocol based on commercially available reusable silicone micromolds and two small molecule growth factor inhibitors to simply and reproducibly generate human neurons from hESC. Hundreds of neurospheres were generated with a single pipettation of hESC into agarose multiwell plates made with the micromolds. This was followed by suspension culture with two medium changes, and plating of clumps cut from the neurospheres on laminin-coated coverslips. After two weeks of terminal differentiation, 90%+ of cells expressed neuronal proteins, and many of the neurons expressed markers of peripheral sensory neurons. The neurons made with this method underwent productive infection with the human-specific pathogenic virus varicella zoster, demonstrating the utility of the neurons for addressing clinically relevant research questions. This simple method should allow laboratories experienced in growing human pluripotent cells to easily generate neurons for studies of nerve cell biology and pathology.

The isolation and characterization of renal cancer initiating cells from human Wilms' tumour xenografts unveils new therapeutic targets

There are considerable differences in tumour biology between adult and paediatric cancers. The existence of cancer initiating cells/cancer stem cells (CIC/CSC) in paediatric solid tumours is currently unclear. Here, we show the successful propagation of primary human Wilms' tumour (WT), a common paediatric renal malignancy, in immunodeficient mice, demonstrating the presence of a population of highly proliferative CIC/CSCs capable of serial xenograft initiation. Cell sorting and limiting dilution transplantation analysis of xenograft cells identified WT CSCs that harbour a primitive undifferentiated – NCAM1 expressing – “blastema” phenotype, including a capacity to expand and differentiate into the mature renal-like cell types observed in the primary tumour. WT CSCs, which can be further enriched by aldehyde dehydrogenase activity, overexpressed renal stemness and genes linked to poor patient prognosis, showed preferential protein expression of phosphorylated PKB/Akt and strong reduction of the miR-200 family. Complete eradication of WT in multiple xenograft models was achieved with a human NCAM antibody drug conjugate. The existence of CIC/CSCs in WT provides new therapeutic targets.

Retrograde axonal transport of VZV: kinetic studies in hESC-derived neurons

Retrograde axonal transport of the neurotropic alphaherpesvirus Varicella zoster virus (VZV) from vesicles at the skin results in sensory neuron infection and establishment of latency. Reactivation from latency leads to painful herpes zoster. The lack of a suitable animal model of these processes for the highly human-restricted VZV has resulted in a dearth of knowledge regarding the axonal transport of VZV. We recently demonstrated VZV infection of distal axons, leading to subsequent capsid transport to the neuronal somata, and replication and release of infectious virus using a new model based on neurons derived from human embryonic stem cells (hESC). In the present study, we perform a kinetic analysis of the retrograde transport of green fluorescent protein-tagged ORF23 in VZV capsids using hESC-derived neurons compartmentalized microfluidic chambers and time-lapse video microscopy. The motion of the VZV was discontinuous, showing net retrograde movement with numerous short pauses and reversals in direction. Velocities measured were higher 1 h after infection than 6 h after infection, while run lengths were similar at both time points. The hESC-derived neuron model was also used to show that reduced neuronal spread by a VZV loss-of-function mutant for ORF7 is not due to the prevention of axonal infection and transport of the virus to the neuronal somata. hESC-derived neurons are, therefore, a powerful model for studying axonal transport of VZV and molecular characteristics of neuronal infection.

Rapid in vivo testing of drug response in multiple myeloma made possible by xenograft to turkey embryos

Background:

The best current xenograft model of multiple myeloma (MM) in immune-deficient non-obese diabetic/severe-combined immunodeficient mice is costly, animal maintenance is complex and several weeks are required to establish engraftment and study drug efficacy. More practical in vivo models may reduce time and drug development cost. We recently described a rapid low-cost xenograft model of human blood malignancies in pre-immune turkey. Here, we report application of this system for studying MM growth and the preclinical assessment of anticancer therapies.

Methods:

Cell lines and MM patient cells were injected intravenously into embryonic veins on embryonic day 11 (E11). Engraftment of human cells in haematopoietic organs was detected by quantitative real-time polymerase chain reaction, immunohistochemistry, flow cytometry and circulating free light chain.

Results:

Engraftment was detected after 1 week in all embryos injected with cell lines and in 50% of those injected with patient cells. Injection of bortezomib or lenalinomide 48 h after cell injection at therapeutic levels that were not toxic to the bone marrow dramatically reduced MM engraftment.

Conclusion:

The turkey embryo provides a practical, xenograft system to study MM and demonstrates the utility of this model for rapid and affordable testing therapeutics in vivo. With further development, this model may enable rapid, inexpensive personalised drug screening.

Primitive stem cells derived from bone marrow express glial and neuronal markers and support revascularization in injured retina exposed to ischemic and mechanical damage

Ischemic or mechanical injury to the optic nerve is an irreversible cause of vision loss, associated with limited regeneration and poor response to neuroprotective agents. The aim of this study was to assess the capacity of adult bone marrow cells to participate in retinal regeneration following the induction of anterior ischemic optic neuropathy (AION) and optic nerve crush (ONC) in a rodent model. The small-sized subset of cells isolated by elutriation and lineage depletion (Fr25lin(-)) was found to be negative for the neuroglial markers nestin and glial fibrillary acidic protein (GFAP). Syngeneic donor cells, identified by genomic marker in sex-mismatched transplants and green fluorescent protein, incorporated into the injured retina (AION and ONC) at a frequency of 0.35%-0.45% after intravenous infusion and 1.8%-2% after intravitreous implantation. Perivascular cells with astrocytic morphology expressing GFAP and vimentin were of the predominant lineage that engrafted after AION injury; 10%-18% of the donor cells incorporated in the retinal ganglion cell layer and expressed NeuN, Thy-1, neurofilament, and beta-tubulin III. The Fr25lin(-) cells displayed an excellent capacity to migrate to sites of tissue disruption and developed coordinated site-specific morphological and phenotypic neural and glial markers. In addition to cellular reconstitution of the injured retinal layers, these cells contributed to endothelial revascularization and apparently supported remodeling by secretion of insulin-like growth factor-1. These results suggest that elutriated autologous adult bone marrow-derived stem cells may serve as an accessible source for cellular reconstitution of the retina following injury.

Efficient generation of schwann cells from human embryonic stem cell-derived neurospheres

Schwann cells (SC), the glial cells of peripheral nerves, are involved in many diseases including Charcot Marie Tooth and neurofibromatosis, and play a pivotal role in peripheral nerve regeneration. Although it is possible to obtain human SC from nerve biopsies, they are difficult to maintain and expand in culture. Here we describe an efficient system for directing the differentiation of human embryonic stem cells (hESC) into cells with the morphological and molecular characteristics of SC. Neurospheres were generated from hESC using stromal cell induction and grown under conditions supportive of SC differentiation. After 8 weeks, hESC-derived SC expressed characteristic markers GFAP, S100, HNK1, P75, MBP and PMP-22, and were observed in close association with hESC-derived neurites. ~60% of the cells were double-immunostained for the SC markers GFAP/S100. RT-PCR analysis confirmed the expression of GFAP, S100, P75, PMP-22 and MBP and demonstrated expression of the SC markers P0, KROX20 and PLP in the cultures. Expression of CAD19 was observed in 2 and 4 week cultures and then was down-regulated, consistent with its expression in SC precursor, but not mature stages. Co-culture of hESC-derived SC with rat, chick or hESC-derived axons in compartmentalized microfluidic chambers resulted in tight association of the SC with axons. Apparent wrapping of the axons by SC was occasionally observed, suggestive of myelination. Our method for generating SC from hESC makes available a virtually unlimited source of human SC for studies of their role in nerve regeneration and modeling of disease.

A rapid and simple assay for human blood malignancy engraftment, homing and chemotherapy treatment using fluorescent imaging of avian embryos

Detection of grafted human cells in mice using fluorescence is a rapid and simple technique whose use is continually expanding. Robust engraftment of human hematological malignancy (HHM) lines and patient cells into the naturally immunodeficient turkey embryo has recently been demonstrated by polymerase chain reaction (PCR), fluorescence activated cell sorting (FACS) and histology. We demonstrate here that fluorescence imaging is a rapid and simple technique for detecting engraftment and homing of cells derived from HHM in turkey embryos. Raji lymphoma cells expressing a far-red fluorescent protein were injected intravascularly into turkey embryos and fluorescence was detected 8 days later in their limbs and skulls. Much stronger signals were obtained after removal of the bones from the limbs. Unlabeled Raji cells did not give a fluorescent signal. Treatment with doxorubicin dramatically reduced the fluorescent signal. Intravenously injected HL-60 leukemia cells labeled with infrared-fluorescing dye were detected in the bone marrow after 16 h. Homing was active, although some non-specific fluorescence was present. Use of fluorescence imaging of HHM in turkey embryos is therefore feasible and reduces the time, effort and expense for detecting engraftment. This technique has potential to become a high-throughput xenograft system for hematological chemotherapy development and testing, and for study of hematological cell homing.

Kidney spheroids recapitulate tubular organoids leading to enhanced tubulogenic potency of human kidney-derived cells

Cell-based approaches utilizing autologous human renal cells require their isolation, expansion in vitro, and reintroduction back into the host for renal tissue regeneration. Nevertheless, human kidney epithelial cells (hKEpCs) lose their phenotype, dedifferentiate, and assume the appearance of fibroblasts after relatively few passages in culture. We hypothesized that growth conditions may influence hKEpC phenotype and function. hKEpCs retrieved from human nephrectomy tissue samples showed the ability to reproducibly form kidney spheres when grown in suspension culture developed in nonadherent conditions. Genetic labeling and time-lapse microscopy indicated, at least in part, the aggregation of hKEpCs into 3D spheroids rather than formation of pure clonally expanded spheres. Characterization of hKEpC spheroids by real-time polymerase chain reaction and FACS analysis showed upregulation of some renal developmental and "stemness" markers compared with monolayer and mostly an EpCAM(+)CD24(+)CD133(+)CD44(+) spheroid cell phenotype. Oligonucleotide microarrays, which were used to identify global transcriptional changes accompanying spheroid formation, showed predominantly upregulation of cell matrix/cell contact molecules and cellular biogenesis processes and downregulation of cell cycle, growth, and locomotion. Accordingly, hKEpC spheroids slowly proliferated as indicated by low Ki-67 staining, but when grafted in low cell numbers onto the chorioallantoic membrane (CAM) of the chick embryo, they exclusively reconstituted various renal tubular epithelia. Moreover, efficient generation of kidney spheroids was observed after long-term monolayer culture resulting in reestablishment of tubulogenic capacity upon CAM grafting. Thus, generation of a tubular organoid in hKEpC spheroids may provide a functional benefit for kidney-derived cells in vivo.

A rapid in vivo assay system for analyzing the organogenetic capacity of human kidney cells

Transplantation of human kidney-derived cells is a potential therapeutic modality for promoting regeneration of diseased renal tissue. However, assays that determine the ability of candidate populations for renal cell therapy to undergo appropriate differentiation and morphogenesis are limited. We report here a rapid and humane assay for characterizing tubulogenic potency utilizing the well-established chorioallantoic membrane CAM) of the chick embryo. Adult human kidney-derived cells expanded in monolayer were suspended in Matrigel and grafted onto the CAM. After a week, grafts were assessed histologically. Strikingly, many of the renal cells self-organized into tubular structures. Host blood vessels penetrated and presumably fed the grafts. Immuno- and histochemical staining revealed that tubular structures were epithelial, but not blood vessels. Some of the cells both within and outside the tubules were dividing. Analysis for markers of proximal and distal renal tubules revealed that grafts contained individual cells of a proximal tubular phenotype and many tubules of distal tubule character. Our results demonstrate that the chick CAM is a useful xenograft system for screening for differentiation and morphogenesis in cells with potential use in renal regenerative medicine.

Proteasome inhibitors sensitize glioma cells and glioma stem cells to TRAIL-induced apoptosis by PKCε-dependent downregulation of AKT and XIAP expressions

In this study we examined the effects of proteasome inhibitors on cell apoptosis in TRAIL-resistant glioma cells and glioma stem cells (GSCs). Treatment with proteasome inhibitors and TRAIL induced apoptosis in all the resistant glioma cells and GSCs, but not in astrocytes and neural progenitor cells. Since PKCε has been implicated in the resistance of glioma cells to TRAIL, we examined its role in TRAIL and proteasome inhibitor-induced apoptosis. We found that TRAIL did not induce significant changes in the expression of PKCε, whereas a partial decrease in PKCε expression was obtained by proteasome inhibitors. A combined treatment of TRAIL and proteasome inhibitors induced accumulation of the catalytic fragment of PKCε and significantly and selectively decreased its protein and mRNA levels in the cancer but not in normal cells. Overexpression of PKCε partially inhibited the apoptotic effect of the proteasome inhibitors and TRAIL, and the caspase-resistant PKCεD383A mutant exerted a stronger inhibitory effect. Silencing of PKCε induced cell apoptosis in both glioma cells and GSCs, further supporting its role in cell survival. TRAIL and the proteasome inhibitors decreased the expression of AKT and XIAP in a PKCε-dependent manner and overexpression of these proteins abolished the apoptotic effect of this treatment. Moreover, silencing of XIAP sensitized glioma cells to TRAIL. Our results indicate that proteasome inhibitors sensitize glioma cells and GSCs to TRAIL by decreasing the expression of PKCε, AKT and XIAP. Combining proteasome inhibitors with TRAIL may be useful therapeutically in the treatment of gliomas and the eradication of GSCs.

Transplantation of mammalian embryonic stem cells and their derivatives to avian embryos

Xenografting of normal and transformed mammalian tissues and cells to chick embryos has been performed for almost 100 years. Embryonic stem cells, derived more than 25 years ago from murine, and more than 10 years ago from human blastocysts, have transformed many fields of biological research. There is a growing body of studies combining these two widely-used experimental systems. This review surveys those reports in which murine or human embryonic stem cells, or differentiated derivatives of these pluripotent stem cells, were transplanted to embryonated chick eggs. Many of these studies have utilized the unique characteristics of both experimental models to obtain answers to developmental questions that are difficult or impossible to approach with xenografting to adult rodents or tissue culture-only techniques.

Whole blood cytokine attenuation by cholinergic agonists ex vivo and relationship to vagus nerve activity in rheumatoid arthritis

OBJECTIVE

The central nervous system regulates innate immunity in part via the cholinergic anti-inflammatory pathway, a neural circuit that transmits signals in the vagus nerve that suppress pro-inflammatory cytokine production by an alpha-7 nicotinic acetylcholine receptors (alpha7nAChR) dependent mechanism. Vagus nerve activity is significantly suppressed in patients with autoimmune diseases, including rheumatoid arthritis (RA). It has been suggested that stimulating the cholinergic anti-inflammatory pathway may be beneficial to patients, but it remains theoretically possible that chronic deficiencies in this pathway will render these approaches ineffective.

METHODS

Here we addressed the hypothesis that inflammatory cells from RA patients can respond to cholinergic agonists with reduced cytokine production in the setting of reduced vagus nerve activity.

RESULTS

Measurement of RR interval variability (heart rate variability, HRV), in RA patients (n = 13) and healthy controls (n = 10) revealed that vagus nerve activity was significantly depressed in patients. Whole blood cultures stimulated by exposure to endotoxin produced significantly less tumour necrosis factor in samples from RA patients as compared to healthy controls. Addition of cholinergic agonists (nicotine and GTS-21) to the stimulated whole blood cultures however significantly suppressed cytokine production to a similar extent in patients and healthy controls.

CONCLUSION

These findings suggest that it is possible to pharmacologically target the alpha7nAChR dependent control of cytokine release in RA patients with suppressed vagus nerve activity. As alpha7nAChR agonists ameliorate the clinical course of collagen induced arthritis in animals, it may be possible in the future to explore whether alpha7nAChR agonists can improve clinical activity in RA patients.

Finders, keepers?: an analysis and validation of a free-found-ad policy

A SURVEY OF LOST AND FOUND CLASSIFIED SECTIONS IN METROPOLITAN AND SMALLER NEWSPAPERS REVEALED DISPARATE RATES BETWEEN LOST ADS AND FOUND ADS: Lost ads greatly outnumbered Found ads, probably because newspapers usually require the finders of lost personal property to pay for Found advertisements. The effect of a Free-Found-Ad policy on the rate of Found advertisements placed in the Lost and Found sections of three community newspapers was investigated using a multiple-baseline design. The results suggested that the Free-Found-Ad policy was effective in increasing the rates of Found ads in all three newspapers. To determine whether increases in Found ads resulted in increases in recovered property, a sample of individuals who placed Found ads were surveyed in both baseline and treatment conditions and asked if the found items had been claimed by their owners. The Free-Found-Ad policy appeared to be effective in increasing the amount of personal property returned. The study concluded that community newspapers can provide incentives to increase such help-giving or altruistic behaviors. The implications of this study for a general policy-research strategy are discussed.

The human skin/chick chorioallantoic membrane model accurately predicts the potency of cosmetic allergens

The current standard method for predicting contact allergenicity is the murine local lymph node assay (LLNA). Public objection to the use of animals in testing of cosmetics makes the development of a system that does not use sentient animals highly desirable. The chorioallantoic membrane (CAM) of the chick egg has been extensively used for the growth of normal and transformed mammalian tissues. The CAM is not innervated, and embryos are sacrificed before the development of pain perception. The aim of this study was to determine whether the sensitization phase of contact dermatitis to known cosmetic allergens can be quantified using CAM-engrafted human skin and how these results compare with published EC3 data obtained with the LLNA. We studied six common molecules used in allergen testing and quantified migration of epidermal Langerhans cells (LC) as a measure of their allergic potency. All agents with known allergic potential induced statistically significant migration of LC. The data obtained correlated well with published data for these allergens generated using the LLNA test. The human-skin CAM model therefore has great potential as an inexpensive, non-radioactive, in vivo alternative to the LLNA, which does not require the use of sentient animals. In addition, this system has the advantage of testing the allergic response of human, rather than animal skin.

Transplantation of human embryonic stem cells and derivatives to the chick embryo

Traditional methods of studying the differentiation of human embryonic stem cells (hESCs) include generation of embryoid bodies, induced differentiation in vitro, and transplantation to immune-deficient mice. The chick embryo is a well-studied and accessible experimental system that has been used for many years as a xenograft host for mammalian cells. Several years ago, we performed experiments transplanting colonies of hESC into organogenesis-stage chick embryos to establish a novel system for studying the developmental programs and decisions of pluripotent human cells. Fluorescent hESC were used, in order to permit identification of the hESC in living embryos. We transplanted hESC into the trunk of chick embryos, both into and instead of developing somites. Our results showed that hESC survive, migrate, and integrate into the tissues of the chick embryo. Some of the hESC differentiated and the type of embryonic microenvironment that the implanted cells were exposed to modified their differentiation. Several other laboratories have subsequently xenografted hESC-derived cells to chick embryos for evaluating their differentiation in vivo. Therefore, the hESC-chick embryo system is a useful xenograft system complementing studies in rodents and in vitro, as well as uniquely shedding light on early processes in the development of human cells in the embryonic context.

PA6-induced human embryonic stem cell-derived neurospheres: a new source of human peripheral sensory neurons and neural crest cells

Human embryonic stem cells (hESC) have been directed to differentiate into CNS cells with clinical importance. However, for study of development and regeneration of the human PNS, and peripheral neuropathies, it would be useful to have a source of human PNS derivatives. We have demonstrated that peripheral sensory neuron-like cells (PSN) can also be derived from hESC via neural crest-like (NC) intermediates, and from neural progenitors induced from hESC using noggin. Here we report the generation of higher purity PSN from passagable neurospheres (NSP) induced by murine PA6 stromal cells. hESC were cultured with PA6, and colonies that developed a specific morphology were cut from the plates. Culture of these colonies under non-adhesive conditions yielded NSPs. Several NC marker genes were expressed in the NSP, and these were also detected in 3-5week gestation human embryos containing migrating NC. These NSPs passaged for 2-8weeks and re-plated on PA6 gave rise to many Brn3a+/peripherin+ cells, characteristic of early sensory-like neurons. Re-culturing PA6-induced NSP cells with PA6 resulted in about 25% of the human cells in the co-cultures differentiating to PSN after 1week, compared to only about 10% PSN obtained after 3 weeks when noggin-induced NSP were used. Two month adherent cultures of PA6-induced NSP cells contained neurons expressing several PSN neuropeptides, and voltage-dependent currents and action potentials were obtained from a molecularly identified PSN. hESC-derived PA6-induced NSP cells are therefore an excellent potential source of human PSN for study of differentiation and modeling of PNS disease.

Anxiety and depression in end-stage COPD

Although feelings of anxiety and depression are common in patients with chronic obstructive pulmonary disease (COPD), estimates of their prevalence vary considerably. This probably reflects the variety of scales and methods used to measure such symptoms. Regardless of whether anxiety and depression are considered separately or as a single construct, their impact on COPD patients is important. A heightened experience of dyspnoea is likely to be a contributing factor to anxiety. Feelings of depression may be precipitated by the loss and grief associated with the disability of COPD. Smoking has been associated with nicotine addiction, and the factors that contribute to smoking may also predispose to anxiety and depressive disorders. Randomised controlled trials indicate that exercise training and carefully selected pharmacological therapy are often effective in ameliorating anxiety and depression. Most medical illnesses are influenced by the psychological responses and coping mechanisms that patients use. However, anxiety and depression are associated with dyspnoea, fatigue and altered sleep, all of which also occur in COPD. An understanding of the psychological history and coping mechanisms of patients and the role of anxiety and depressive reactions to illness may enable clinicians to reduce these symptoms and improve quality of life among patients with chronic obstructive pulmonary disease.

Meta-analysis of respiratory rehabilitation in chronic obstructive pulmonary disease. A Cochrane systematic review

BACKGROUND

The widespread application of pulmonary rehabilitation in chronic obstructive pulmonary disease (COPD) should be preceded by demonstrable improvements in function attributable to the programs.

OBJECTIVES

To determine the impact of rehabilitation on health-related quality of life (QoL) and exercise capacity in patients with COPD.

METHODS

We identified randomized controlled trials (RCTs) from the Cochrane Airways Group Specialised Register. We selected RCTs of rehabilitation in patients with COPD in which quality of life (QoL) and/or exercise capacity were measured. Rehabilitation was defined as exercise training for at least 4 weeks with or without education and/or psychological support. Control groups received conventional community care without rehabilitation.

RESULTS

A total of 31 RCTs met the inclusion criteria. We found statistically significant improvements for all the outcomes. In 4 important domains of QoL (Chronic Respiratory Questionnaire scores for Dyspnea, Fatigue, Emotional function and Mastery), the effect was larger than the minimal clinically important difference. For exercise capacity, the effect was small and slightly below the threshold of clinical significance for the six-minute walking distance (WMD: 48 m; 95% CI: 32 to 65; n = 16 trials).

CONCLUSIONS

Rehabilitation relieves dyspnea and fatigue, improves emotional function and enhances patients' control over their condition. These improvements are moderately large and clinically significant. Rehabilitation forms an important component of the management of COPD.

Counting, analysing and reporting exacerbations of COPD in randomised controlled trials

BACKGROUND

Clinical trials measure exacerbations of chronic obstructive pulmonary disease (COPD) inconsistently. A study was undertaken to determine if different methods for ascertaining and analysing COPD exacerbations lead to biased estimates of treatment effects.

METHODS

Information on the methods used to count, analyse and report COPD exacerbation rates was abstracted from clinical trials of long-acting bronchodilators or long-acting bronchodilator/inhaled steroid combination products published between 2000 and 2006. Data from the Canadian Optimal Therapy of COPD Trial was used to illustrate how different analytical approaches can affect the estimate of exacerbation rates and their confidence intervals.

RESULTS

22 trials (17,156 patients) met the inclusion criteria and were reviewed. None of the trials adjudicated exacerbations or determined independence of events. 14/22 studies (64%) introduced selection bias by not analysing outcome data for subjects who prematurely stopped study medications. Only 31% of trials used time-weighted analyses to calculate the mean number of exacerbations/patient-year and only 15% accounted for between-subject variation. In the Canadian Optimal Therapy of COPD Trial the rate ratio for exacerbations/patient-year was 0.85 when all data were included in a time-weighted analysis, but was overestimated as 0.79 when data for those who prematurely stopped study medications were excluded and was further overestimated as 0.46 when a time-weighted analysis was not conducted; p values ranged from 0.03 to 0.24 depending on how exacerbations were determined and analysed.

CONCLUSIONS

Clinical trials have used widely different methods to define and analyse COPD exacerbations and this can lead to biased estimates of treatment effects. Future trials should strive to include blinded adjudication and assessment of the independence of exacerbation events, and trials should report time-weighted intention-to-treat analyses with adjustments for between-subject variation in COPD exacerbations.

Peripheral sensory neurons differentiate from neural precursors derived from human embryonic stem cells

Neural precursors have been derived from human embryonic stem cells (hESC) using the bone morphogenetic protein antagonist noggin. These neural precursors can be further differentiated to produce neural cells that express central nervous system (CNS) markers. We have recently shown that naive hESC can be directed to differentiate into peripheral sensory (PS) neuron-like cells and putative neural crest precursors by co-culturing with PA6 stromal cells. In the present study, we examine whether hESC-derived neural precursors (NPC) can differentiate into the peripheral nervous system, as well as CNS cells. As little as 1 week after co-culture with PA6 cells, cells with the molecular characteristics of PS neurons and neural crest are observed in the cultures. With increased time in culture, more PS-like neurons appear, in parallel with a reduction in the neural crest-like cells. These results provide the first evidence that neural precursors derived from hESC have the potential to develop into PS neurons-like as well as CNS-like neuronal cells. About 10% of the cells in NPC-PA6 co-cultures express PS neuron markers after 3 weeks, compared with <1% of hESC cultured on PA6. This enrichment for peripheral neurons makes this an attractive system for generation of peripheral neurons for pathophysiology study and drug development for diseases of the peripheral nervous system such as Familial Dysautonomia and varicella virus infection.

Immunological activation following transcutaneous delivery of HR-gp100 protein

Transcutaneous immunization aims at taking advantage of the skin's immune system for the purpose of immunoprotection. In the present study, we evaluated the potential of topical delivery of a recombinant melanoma protein, HR-gp100, derived from a shortened sequence of the native gp100 gene. The protein was applied on the skin, with and without the addition of two forms of heat labile enterotoxin (nLT and LTB). HR-gp100 fused to Haptide, a cell penetrating 20mer peptide (HR-gp100H) was also tested. Topical HR-gp100 and HR-gp100H application on the ears of mice elicited the production of specific antibodies, and transcutaneous delivery to intact human skin induced dose-dependent LC activation. nLT and LTB also activated LC, but did not further increase the activation induced by HR-gp100. These results show that HR-gp100, an antigenic tumor-derived protein, activates the immune system following transcutaneous delivery, as shown by both Langerhans cell activation and induction of antibody production.

Oxygen therapy during exercise training in chronic obstructive pulmonary disease

BACKGROUND

Exercise training within the context of pulmonary rehabilitation improves outcomes of exercise capacity, dyspnea and health-related quality of life in individuals with chronic obstructive pulmonary disease (COPD). Supplemental oxygen in comparison to placebo increases exercise capacity in patients performing single-assessment exercise tests. The addition of supplemental oxygen during exercise training may enable individuals with COPD to tolerate higher levels of activity with less exertional symptoms, ultimately improving quality of life.

OBJECTIVES

To determine how supplemental oxygen in comparison to control (compressed air or room air) during the exercise-training component of a pulmonary rehabilitation program affects exercise capacity, dyspnea and health-related quality of life in individuals with COPD.

SEARCH STRATEGY

All records in the Cochrane Airways Group Specialized Register of trials coded as 'COPD' were searched using the following terms: (oxygen* or O2*) AND (exercis* or train* or rehabilitat* or fitness* or physical* or activ* or endur* or exert* or walk* or cycle*). Searching the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library), MEDLINE, EMBASE and CINAHL databases identified studies. The last search was carried out in June 2006.

SELECTION CRITERIA

Only randomized controlled trials (RCTs) comparing oxygen-supplemented exercise training to non-supplemented exercise training (control group) were considered for inclusion. Participants were 18 years or older, diagnosed with COPD and did not meet criteria for long-term oxygen therapy. No studies with mixed populations (pulmonary fibrosis, cystic fibrosis, etc) were included. Exercise training was greater than or equal to three weeks in duration and included a minimum of two sessions a week.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials for inclusion in the review and extracted data. Weighted mean differences (WMD) with 95% confidence intervals (CI) were calculated using a random-effects model. Missing data were requested from authors of primary studies.

MAIN RESULTS

Five RCTs met the inclusion criteria. The maximum number of studies compared in the meta-analysis was three (31 on oxygen versus 32 control participants), because all included studies did not measure the same outcomes. When two studies were pooled, statistically significant improvements of oxygen-supplemented exercise training were found in constant power exercise time, WMD 2.68 minutes (95% CI 0.07 to 5.28 minutes). Supplemental oxygen increased the average exercise time from 6 to 14 minutes; the control intervention increased average exercise time from 6 to 12 minutes. Constant power exercise end-of-test Borg score (on a scale from 1 to 10) also showed statistically significant improvements with oxygen-supplemented exercise training, WMD -1.22 units (95% CI -2.39 to -0.06). One study showed a significant improvement in the change of Borg score after the shuttle walk test, by -1.46 units (95% CI -2.72 to -0.19). There were no significant differences in maximal exercise outcomes, functional exercise outcomes (six-minute walk test), shuttle walk distance, health-related quality of life or oxygenation status. According to the GRADE system most outcomes were rated as low quality because they were limited by study quality.

AUTHORS' CONCLUSIONS

This review provides little support for oxygen supplementation during exercise training for individuals with COPD, but the evidence is very limited. Studies with larger number of participants and strong design are required to permit strong conclusions, especially for functional outcomes such as symptom alleviation, health-related quality of life and ambulation.

Perspectives that influence action plans for chronic obstructive pulmonary disease

BACKGROUND

Prompt treatment of acute exacerbations (AEs) in chronic obstructive pulmonary disease (COPD) improves quality of life and reduces the use of health care resources. Although patient self-management through an individualized action plan (AP) can help with early initiation of therapy, its use is critically dependent on the patient recognizing the features of an exacerbation.

OBJECTIVE

To describe COPD patients' experiences with AEs, as well as health care professionals' (HCPs') attitudes toward the provision of an AP as part of self-management education.

METHODS

Thirty-two patients with moderate to severe COPD who recently experienced at least one AE, and 22 HCPs with experience in the management of COPD, were interviewed.

RESULTS

The most common symptoms and signs associated with an AE were difficulty breathing (84%), fatigue (81%), cold symptoms (59%), changes in sputum colour (53%) or amount (47%), and cough (44%). The main precipitants identified were environmental triggers (47%), infective agents (31%), excessive activities (25%), emotional factors (16%) and changes in medications (9%). Strategies for dyspnea relief included increasing medications (72%), resting (56%), avoiding exposure to environmental triggers (41%) and performing breathing exercises (31%). Patients supported the use of an AP and recommended that it be individualized for symptoms and triggers, and that it should also include strategies for addressing anxiety and depression. HCPs also supported the use of an individualized AP and recommended that it be regularly revisited, depending on the patient's disease severity.

CONCLUSIONS

Patients' experiences with AEs do not always conform to a standard medical definition. Therefore, an understanding of their experience is of value in the design of an individualized AP. HCPs support the use of an AP that emphasizes self-management of exacerbations as well as general COPD management.

A novel and rapid in vivo system for testing therapeutics on human leukemias

OBJECTIVE

To develop a novel in vivo system for rapid assessment of leukemia growth and treatment of human blood cell malignancies.

MATERIALS AND METHODS

Cell lines derived from several human hematologic malignancies were introduced into chick embryos using four different methods.

RESULTS

K562 cells engraft in 100% of embryos following intravascular or intra-amniotic injection. The engraftment is rapid, appearing as soon as 7 days after injection, in striking contrast to the 4 weeks and more required for engrafting severe combined immunodeficient mice with human leukemia by systemic injection. The engraftment is easily visualized in vivo as tumor nodules in the chicken chorioallantoic membrane (CAM). In addition, leukemia is consistently detected in the embryos' hematopoietic organs by polymerase chain reaction amplification of human-specific DNA sequences. Consistent engraftment was also obtained using another leukemia cell line (DAMI). Finally, we demonstrate proof of principle that this system can be used for testing the efficacy of chemotherapy agents. Dramatic and consistent regression of tumors in the CAM was induced by a single intravenous dose of doxorubicin administered to K562-engrafted embryos.

CONCLUSION

This in vivo system provides a new platform for studying human blood cell malignancies at much lower cost than other animal models and has the potential to provide rapid chemotherapy assays, which could significantly reduce drug development time and expense.

Transplantation of human embryonic stem cells to the chick embryo

The traditional methods of studying the differentiation of human embryonic stem cells (hESCs) are to differentiate them in vitro or in immune-deficient mice as teratomas. The chick embryo is a well-studied and accessible experimental system that has been shown to permit the development of mammalian cells, including murine embryonic stem cells. We therefore performed experiments transplanting colonies of hESCs into organogenesis-stage chick embryos, hoping this might provide a novel system for studying the developmental programs and decisions of these important cells. hESCs, constitutively expressing green fluorescent protein or labeled with the dye CFDA, were used to allow the following the hESC in living embryos. As a first step, we chose to transplant hESCs into the trunk of chick embryos, both into and instead of developing somites. Our first results showed that hESCs survive, migrate, and integrate into the tissues of the chick embryo. Some of the hESCs differentiate and the type of embryonic microenvironment that the implanted cells were exposed to modified their differentiation. Therefore, this hESC-chick embryo system has potential for complementing studies in rodents and in vitro, and uniquely, to shed light on early processes in the development of human cells in the embryonic context.

Derivation of neural precursors from human embryonic stem cells in the presence of noggin

The utilization of human embryonic stem cells (hESC) for basic and applied research is hampered by limitations in directing their differentiation. Empirical poorly defined methods are currently used to develop cultures enriched for distinct cell types. Here, we report the derivation of neural precursors (NPs) from hESC in a defined culture system that includes the bone morphogenetic protein antagonist noggin. When hESC are cultured as floating aggregates in defined medium and BMP signaling is repressed by noggin, non-neural differentiation is suppressed, and the cell aggregates develop into spheres highly enriched for proliferating NPs. The NPs can differentiate into astrocytes, oligodendrocytes, and mature electrophysiologically functional neurons. During prolonged propagation, the differentiation potential of the NPs shifts from neuronal to glial fate. The presented noggin-dependent controlled conversion of hESC into NPs is valuable for the study of human neurogenesis, the development of new drugs, and is an important step towards the potential utilization of hESC in neural transplantation therapy.

Generation of peripheral sensory and sympathetic neurons and neural crest cells from human embryonic stem cells

Human embryonic stem cells (hESCs) have been directed to differentiate into neuronal cells using many cell-culture techniques. Central nervous system cells with clinical importance have been produced from hESCs. To date, however, there have been no definitive reports of generation of peripheral neurons from hESCs. We used a modification of the method of Sasai and colleagues for mouse and primate embryonic stem cells to elicit neuronal differentiation from hESCs. When hESCs are cocultured with the mouse stromal line PA6 for 3 weeks, neurons are induced that coexpress (a) peripherin and Brn3a, and (b) peripherin and tyrosine hydroxylase, combinations characteristic of peripheral sensory and sympathetic neurons, respectively. In vivo, peripheral sensory and sympathetic neurons develop from the neural crest (NC). Analysis of expression of mRNAs identified in other species as NC markers reveals that the PA6 cells induce NC-like cells before neuronal differentiation takes place. Several NC markers, including SNAIL, dHAND, and Sox9, are increased at 1 week of coculture relative to naive cells. Furthermore, the expression of several NC marker genes known to be downregulated upon in vivo differentiation of NC derivatives, was observed to be present at lower levels at 3 weeks of PA6-hESC coculture than at 1 week. Our report is the first on the expression of molecular markers of NC-like cells in primates, in general, and in humans, specifically. Our results suggest that this system can be used for studying molecular and cellular events in the almost inaccessible human NC, as well as for producing normal human peripheral neurons for developing therapies for diseases such as familial dysautonomia.

Nutritional supplementation for stable chronic obstructive pulmonary disease

BACKGROUND

Low body weight in patients with chronic obstructive pulmonary disease (COPD) is associated with an impaired pulmonary status, reduced diaphragmatic mass, lower exercise capacity and higher mortality rate when compared to adequately nourished individuals with this disease. Nutritional support may therefore be a useful part of their comprehensive care.

OBJECTIVES

To conduct a systematic review of randomised controlled trials (RCTs) to clarify whether nutritional supplementation (caloric supplementation for at least 2 weeks) improved anthropometric measures, pulmonary function, respiratory muscle strength and functional exercise capacity in patients with stable COPD.

SEARCH STRATEGY

Randomized controlled trials (RCTs) were identified from the Cochrane Airways Group register of RCTs, a hand-search of abstracts presented at international meetings and consultation with experts. Searches are current as of March 2004.

SELECTION CRITERIA

Two reviewers independently selected trials for inclusion, assessed quality and extracted the data.

DATA COLLECTION AND ANALYSIS

Within each trial and for each outcome, we calculated an effect size. The effect sizes were then pooled by a random-effects model. Homogeneity among the effect sizes was also tested.

MAIN RESULTS

Eleven studies recruiting 352 participants met the inclusion criteria. Eight papers were considered as high quality. Two studies were double-blinded. For each of the outcomes studied, the effect of nutritional support was small: the 95% confidence intervals around the pooled effect sizes all included zero. The effect of nutritional support was homogeneous across studies.

AUTHORS' CONCLUSIONS

Nutritional support had no significant effect on anthropometric measures, lung function or exercise capacity in patients with stable COPD.

Effects of male and female sex steroids on the development of normal and the transient Froriep's dorsal root ganglia of the chick embryo

Sex steroids can influence developmental processes and support the survival of neurons in the embryonic central nervous system. Recent studies have shown that estrogen receptors are also expressed in the peripheral nervous system, in the dorsal root ganglia (DRG) of chick embryos. However, no studies have examined the effects of sex steroids on development of embryonic DRG. In the present study, 0.2 microg, 1.0 microg, 5.0 microg 10 microg, 20 microg, 25 microg, and 40 microg doses of testosterone or estradiol were delivered to chick embryos at Hamburger and Hamilton stage 18 (E3). The actions of these doses of sex steroids on the development of the C5DRG (fifth cervical ganglion, a "normal" DRG) and C2DRG (a transient ganglion known as a "Froriep's DRG") were then evaluated by quantifying ganglionic volumes, cell number, proliferation, and apoptosis after 1 day of growth to stage 23. We found that both testosterone and estradiol promoted proliferation of cells in both normal DRG and the Froriep's ganglia. By contrast, estradiol significantly increased the number of apoptotic cells, while testosterone strongly inhibited apoptosis. These actions of sex steroids on DRG development were dose-dependent, and C5DRG and C2DRG showed different sensitivities to the applied sex steroids. In addition, the present results demonstrated that specific ER and AR inhibitors (tamoxifen and flutamide) did not influence the effects of 5 microg E2 and 5 microg T on C2 and C5DRG significantly. These results demonstrate that male and female sex steroids can modulate DRG development through an epigenetic mechanism, as had been shown for the central nervous system.