Early Events in Xenograft Development from the Human Embryonic Stem Cell Line HS181 - Resemblance with an Initial Multiple Epiblast Formation

Xenografting is widely used for assessing in vivo pluripotency of human stem cell populations. Here, we report on early to late events in the development of mature experimental teratoma from a well-characterized human embryonic stem cell (HESC) line, HS181. The results show an embryonic process, increasingly chaotic. Active proliferation of the stem cell derived cellular progeny was detected already at day 5, and characterized by the appearance of multiple sites of engraftment, with structures of single or pseudostratified columnar epithelium surrounding small cavities. The striking histological resemblance to developing embryonic ectoderm, and the formation of epiblast-like structures was supported by the expression of the markers OCT4, NANOG, SSEA-4 and KLF4, but a lack of REX1. The early neural marker NESTIN was uniformly expressed, while markers linked to gastrulation, such as BMP-4, NODAL or BRACHYURY were not detected. Thus, observations on day 5 indicated differentiation comparable to the most early transient cell populations in human post implantation development. Confirming and expanding on previous findings from HS181 xenografts, these early events were followed by an increasingly chaotic development, incorporated in the formation of a benign teratoma with complex embryonic components. In the mature HS181 teratomas not all types of organs/tissues were detected, indicating a restricted differentiation, and a lack of adequate spatial developmental cues during the further teratoma formation. Uniquely, a kinetic alignment of rare complex structures was made to human embryos at diagnosed gestation stages, showing minor kinetic deviations between HS181 teratoma and the human counterpart

Human antimicrobial protein hCAP18/LL-37 promotes a metastatic phenotype in breast cancer

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Differentiation in Neuroblastoma: Diffusion-Limited Hypoxia Induces Neuro-Endocrine Secretory Protein 55 and Other Markers of a Chromaffin Phenotype

Background: Neuroblastoma is a childhood malignancy of sympathetic embryonal origin. A high potential for differentiation is a hallmark of neuroblastoma cells. We have previously presented data to suggest that in situ differentiation in tumors frequently proceeds along the chromaffin lineage and that decreased oxygen ( hypoxia) plays a role in this. Here we explore the utility of Neuro-Endocrine Secretory Protein 55 ( NESP55), a novel member of the chromogranin family, as a marker for this process.Methodology/Principal Findings: Immunohistochemical analyses and in situ hybridizations were performed on human fetal tissues, mouse xenografts of human neuroblastoma cell lines, and on specimens of human neuroblastoma/ganglioneuroma. Effects of anaerobic exposure on gene expression by cultured neuroblastoma cells was analyzed with quantitative real-time PCR. Fetal sympathetic nervous system expression of NESP55 was shown to be specific for chromaffin cell types. In experimental and clinical neuroblastoma NESP55 immunoreactivity was specific for regions of chronic hypoxia. NESP55 expression also correlated strikingly with morphological evidence of differentiation and with other chromaffin-specific patterns of gene expression, including IGF2 and HIF2 alpha. Anaerobic culture of five neuroblastoma cell lines resulted in an 18.9-fold mean up-regulation of NESP55.Conclusions/Significance: The data confirms that chronic tumor hypoxia is a key microenvironmental factor for neuroblastoma cell differentiation, causing induction of chromaffin features and NESP55 provides a reliable marker for this neuronal to neuroendocrine transition. The hypoxia-induced phenotype is the predominant form of differentiation in stroma-poor tumors, while in stroma-rich tumors the chromaffin phenotype coexists with ganglion cell-like differentiation. The findings provide new insights into the biological diversity which is a striking feature of this group of tumors

Studies on malignant ventricular tachyarrhythmias and their treatment with an implantable defibrillator

Aims: To investigate the hemodynamic, metabolic and autonomic effects of ventricular fibrillation per se during maintained circulation. To study the defibrillation threshold (DFT) and efficacy of a new and thinner ICD lead (DSP) compared with the standard lead (C). To study the effects of pectoral or abdominal generator positioning on bidirectional and biphasic defibrillation. To study if the results of perioperative induction testing data would make postoperative ICD induction testing unnecessary. The evaluate the effects of time, exercise and amiodarone on an electrogram morphology discriminator. Methods: The coronary sinus flow (CSF), systemic and left ventricular pressure, myocardial oxygen consumption, metabolic products and catecholamine were analyzed in patients with aortic stenosis during induction of ventricular fibrillation (VF) with ongoing cardiopulmonary bypass. DSP and C leads DFT and pacing data from implantation and during follow-up were compared. The effect on DFT was studied by an alternating step-down protocol with an ICD in abdominal and a pectoral position in the same patient. Peroperative and postoperative ICD induction tests were performed and the relative and absolute defibrillation energy efficacy was analyzed. The effects of time, exercise and amiodarone therapy on the algorithm function were studied.Results: Myocardial ischemia, acidosis and a temporary noradrenalin net release developed during 4 min of VF despite an unchanged CSF and global myocardial oxygen consumption. The aortic and left ventricular pressure equilibrated rapidly after start of VF start. In the DSP both performed equally well. Abdominal or pectoral position did not affect the DFT. A relative energy of d 10J and an absolute defibrillation energy of T 20J at implantation could have made 89% of the predischarge tests unnecessary. The mean long-term MD function was not changed over time, at exercise or treatment of amiodarone. Transient miss-classification of electrograms occurred over time and during tachycardias.Conclusions: VF, per se, rapidly induced signs of myocardial ischemia, acidosis and a transient increase in noradrenaline release as well as an equilibration of the left ventricular and aortic pressures. Both the DSP and the C electrode were safe and effective in the treatment of ventricular tachyarrhythmias. No difference was found between the abdominal and pectoral positions in the same patient. The combined criteria of a relative defibrillation margin of 10 J and an absolute energy of 20 J at ICD implantation could be used without risk to reduce the need of postoperative induction testing to 11%. The morphological electrogram discrimination function showed stable mean values over time, during an exercise test and during amiodarone treatment. Single, transient, false low morphology discrimination scores were found during follow-up. The morphology discrimination must be frequently automatically updated and combined with other detection enhancements

Kostmann disease and other forms of severe congenital neutropenia

Congenital neutropenia with autosomal recessive inheritance was first described by the Swedish paediatrician Rolf Kostmann who coined the term ‘infantile genetic agranulocytosis’. The condition is now commonly referred to as Kostmann disease. These patients display a maturation arrest of the myelopoiesis in the bone marrow and reduced neutrophil numbers and suffer from recurrent, often life-threatening infections. The molecular mechanism underlying congenital neutropenia has been intensively investigated, and mutations in genes that impinge on programmed cell death have been identified. The present review provides an overview of these studies

Hyrtl's anastomosis is normally developed in placentas from small for gestational age infants.

Background. The aim of this study was to investigate the occurrence and appearance of the anastomosis between the two umbilical arteries in placentas from infants small for gestational age (SGA). Methods. The arterial systems of 64 placentas from singleton pregnancies resulting in SGA infants were visualized by angiography. The method allowed study of the anastomosis between the umbilical arteries and calculation of the relative placental area supplied by each artery. The results were compared with findings in a previous study of appropriate for gestational age (AGA) infants. One-way analysis of variance (anova) and chi2-analyses were used for statistics. Results. In 56 placentas the anastomosis was represented by a true vessel, in two by a fenestration, and in another two cases by fusion of the umbilical arteries. The anastomosis was absent in one case and another three cases had a single umbilical artery (SUA). When the diameter of the anastomosis was thinner than that of the umbilical arteries, their supply areas were significantly (p <= 0.001) more symmetrical than in cases with a wider anastomosis. The anatomy of the anastomosis and the relationship between its width and the symmetry between the supply areas of each umbilical artery did not differ in placentas from SGA and AGA infants, despite various types of cord insertion and placentation. Conclusion. Static measurements of Hyrtl's anastomosis do not indicate a contributing part for intrauterine growth retardation

SIX1 protein expression selectively identifies blastemal elements in Wilms tumor.

BACKGROUND: Wilms tumor (WT) is the most common renal neoplasm in children. Histologically, most WTs consist of three tissue elements: blastema, epithelium, and stroma. Some cases also show diffuse or focal anaplastic features. Previous studies have shown that a predominance of blastemal cells in post-chemotherapy WT specimens is associated with a poor clinical course. However, there is currently no molecular marker for blastemal cells, and risk stratification for post-nephrectomy treatment is therefore often based on clinico-histological parameters alone. PROCEDURE: In the present study, three public gene expression microarray datasets, including 82 WTs and 8 normal fetal kidneys, were used to establish a consensus gene expression profile of WT. By bioinformatic analyses, 17 genes overexpressed in WT compared to fetal kidney were then selected for evaluation of their protein expression in WT cell lines and in the different histological components in paraffin-embedded WT tissue sections by immunofluorescence. RESULTS: Most of the evaluated proteins were expressed in all three common histological components. A prominent exception was SIX1, being expressed predominantly in blastemal elements in 24/25 pediatric cases containing blastema. Anaplastic elements exhibited highly variable SIX1-positivity. The SIX2 protein, known to be co-expressed with SIX1 during nephrogenesis, only exhibited blastemal-predominant expression in half of the SIX2 evaluated cases. CONCLUSIONS: Genes highly expressed in WT compared to fetal kidney are generally overexpressed in all of the three common WT tissue elements. An exception is the predominant expression of SIX1 in blastemal cells, hereby identifying this protein as a candidate marker for blastema. Pediatr Blood Cancer © 2011 Wiley Periodicals, Inc