Pluripotent stem cells are protected from cytomegalovirus infection at multiple points: Implications of a new pathogenesis for congenital anomaly caused by cytomegalovirus

In humans, the cytomegalovirus (CMV) is the most significant cause of intrauterine infections that cause congenital anomalies. Intrauterine infection with human CMV is thought to be responsible for a variety of abnormalities, including mental retardation, microcephaly, developmental delay, seizure disorders, and cerebral palsy, depending on the timing of the fetal infection, the infectious route, and the virulence of the virus. In addition to the adaptive immune system, the embryo has potential resistance to CMV during early embryogenesis. Embryonic stem (ES) cells are more resistant to CMV than most other cell types, although the mechanism responsible for this resistance is not well understood. ES cells allow approximately 20-fold less murine CMV (MCMV) DNA to enter the nucleus than mouse embryonic fibroblasts (MEFs), and this inhibition occurs in a multistep manner. In situ hybridization showed that ES cell nuclei had significantly less MCMV DNA than MEF nuclei. This finding appears to be supported by the fact that ES cells express less heparan sulfate, β1-integrin, and vimentin and have fewer nuclear pores than differentiated cells such as MEF. This may reduce the ability of MCMV to attach to and enter the cellular membrane, translocate to the nucleus, and cross the nuclear membrane in pluripotent stem cells (ES-induced pluripotent stem cells). This finding may indicate a new pathogenesis for the congenital anomaly caused by CMV.     

Annual Research Review: The promise of stem cell research for neuropsychiatric disorders

The study of the developing brain has begun to shed light on the underpinnings of both early and adult onset neuropsychiatric disorders. Neuroimaging of the human brain across developmental time points and the use of model animal systems have combined to reveal brain systems and gene products that may play a role in autism spectrum disorders, attention deficit hyperactivity disorder, obsessive compulsive disorder and many other neurodevelopmental conditions. However, precisely how genes may function in human brain development and how they interact with each other leading to psychiatric disorders is unknown. Because of an increasing understanding of neural stem cells and how the nervous system subsequently develops from these cells, we have now the ability to study disorders of the nervous system in a new way - by rewinding and reviewing the development of human neural cells. Induced pluripotent stem cells (iPSCs), developed from mature somatic cells, have allowed the development of specific cells in patients to be observed in real time. Moreover, they have allowed some neuronal-specific abnormalities to be corrected with pharmacological intervention in tissue culture. These exciting advances based on the use of iPSCs hold great promise for understanding, diagnosing and, possibly, treating psychiatric disorders. Specifically, examination of iPSCs from typically developing individuals will reveal how basic cellular processes and genetic differences contribute to individually unique nervous systems. Moreover, by comparing iPSCs from typically developing individuals and patients, differences at stem cell stages, through neural differentiation, and into the development of functional neurons may be identified that will reveal opportunities for intervention. The application of such techniques to early onset neuropsychiatric disorders is still on the horizon but has become a reality of current research efforts as a consequence of the revelations of many years of basic developmental neurobiological science.     

New approaches to hematopoietic cell transplantation in oncology

The use of high-dose chemotherapy followed by autologous HCT and the use of allogeneic HCT in children and adolescents with high-risk ALL, AML, and NBL has successfully improved outcomes. For other diseases, however, the role of HCT in treatment remains a subject of further research. The availability of HCT was significantly expanded by developing alternative graft sources that currently include BM, peripheral blood, and UCB from autologous and allogeneic related or unrelated donors. Progress in autologous HCT has been achieved by the identification of more effective and less toxic preparative regimens and by ex vivo purging of stem cell products. In allogeneic HCT, graft-versus-leukemia or graft-versus-tumor effects are being exploited increasingly to lower relapse rates. In addition, immunomodulation to promote tolerance, as well as allogeneic antitumor reactions have been achieved by antibody therapy, cytokine therapy, or cell-based immunotherapy. Future improvements are likely, as evidenced by promising preliminary results in the development of stem cell collection techniques, in vitro stem cell expansion, and purging techniques of stem cell grafts. The development of less intensive or nonmyeloablative preparative regimens may further reduce regimen-related morbidity and mortality Specific immunotherapy may facilitate tolerance induction in mismatched allogeneic HCT and support allogeneic HCT in the setting of donor-host HLA disparity. Ultimately, advances in cytokine therapy, tumor-specific vaccines, and gene therapy may decrease or even eradicate recurrence of the malignant disease after HCT.     

Environmental thyroid toxicants and child endocrine health

Humans are continuously exposed to many man-made chemicals, which are environmentally persistent and often hormone-like active. Substantial in vitro and in vivo evidence indicate that polyhalogenated aromatic pollutants, such as dioxins,furans,polychlorinated biphenyls and polybrominated diphenylethers, can adversely affect thyroid function mainly resulting in hypothyroidism. Although most studies on human background-exposure have as yet failed consistently to associate thyroid function with environmental toxicants, current views point towards subtle or transient impairment of thyroid secretion. Small hormonal changes chemically induced, though within normal reference ranges, may have negative consequences for the developing individual. In particular, the fetus and the neonate/infant may be vulnerable to subtle changes of thyroid function as their turnover of the thyroid hormonal store is very rapid and they may become depleted more rapidly than adults. This critical developmental phase may be vulnerable to even subtle toxicant effects on the thyroid system. Moreover, data inconsistencies may be related to sample size limitations and methodological issues, including mixed toxicant congener exposure that has precluded conclusions about chemical congeners per se. More studies are crucial to fill in the research gaps regarding permanent endocrine and neurological outcome in next generations exposed to background thyroid toxicants.     

间充质干细胞向上皮细胞的诱导分化及应用研究进展

间充质干细胞( mesenchymal stem cell,MSC)在体内外可被诱导分化为多种上皮细胞,如肺泡上皮、肾小管上皮和角膜上皮细胞等,表达上皮细胞特异性标志.MSC回输体内后,可有效修复损伤的肺上皮细胞组织,缓解炎症损伤,减轻肾小管细胞损伤、减少肾间质炎症细胞浸润,促进肾小管上皮细胞再生,并抑制细胞凋亡;也可...     

Hereditary cancer and developmental abnormalities

About 1% of all cancers are hereditary, caused by germ-line mutations in specific cancer-related genes. More than 25 different hereditary cancer syndromes are known, most of them involving mutations in tumor suppressor genes. These genes, which are related to cellular proliferation, might also be involved in differentiation. Hence, the phenotype of hereditary cancer syndromes might include developmental abnormalities, in addition to cancer predisposition. The information summarized here indicates that developmental phenotypes appear in both human patients and mouse models of the various hereditary cancer syndromes. These developmental abnormalities, which involve a variety of tissues and organs, usually lead to embryonic malformation that prevents the birth of viable homozygous offspring, but can also be detected in heterozygotes. In some of the syndromes a correlation exists between tumor types and developmentally affected tissues. Comparison of mice and human phenotypes from both the cancer and the developmental aspects indicates that many of the mouse models mimic the human syndromes. Our analysis indicates that most tumor suppressor genes participate not only in the regulation of cell proliferation, but also in differentiation and embryogenesis.     

Neural stem cells: properties and therapeutic potentials for hypoxic‐ischemic brain injury in newborn infants

Neural stem cells (NSCs) are defined by their ability to self‐renew, to differentiate into cells of all glial and neuronal lineages throughout the neuraxis, and to populate developing or degenerating central nervous system (CNS) regions. The recognition that NSCs propagated in culture could be reimplanted into the mammalian brain, where they might integrate appropriately throughout the mammalian CNS and stably express foreign genes, has unveiled a new role for neural transplantation and gene therapy and a possible strategy for addressing the CNS manifestations of diseases that hitherto had been refractory to intervention. An intriguing phenomenon with possible therapeutic potentials has begun to emerge from our observations of the behavior of NSCs in animal models of neonatal hypoxic‐ischemic (HI) brain injury. During phases of active neurodegeneration, factors seem to be transiently elaborated to which NSCs may respond by migrating to degenerating regions and differentiating specifically towards replacement of dying neural cells. NSCs may attempt to repopulate and reconstitute ablated regions. These ‘repair mechanisms’ may actually reflect the reexpression of basic developmental principles that may be harnessed for therapeutic ends. In addition, NSCs may serve as vehicles for gene delivery and appear capable of simultaneous neural cell replacement and gene therapy (e.g. with factors that might enhance neuronal differentiation, neurites outgrowth, proper connectivity, and/or neuroprotection). When combined with certain synthetic biomaterials, NSCs may be even more effective in ‘engineering’ the damaged CNS towards reconstitution. We have also cultured human NSCs or progenitors as neurospheres which were derived from fetal cadavers at 13 weeks of gestation, and transplanted them into HI‐injured immature brains to investigate their therapeutic potentials in this type of model.     

Experimental split cord malformations

OBJECTIVE: To induce experimental split cord malformations (SCMs) produced through the surgical induction of a dorsal midline fistula. METHODS: In addition, the theory of embryogenesis of SCMs was verified by examining the developmental process of this experimentally induced anomaly. In Cynopus pyrrhogaster (amphibian) embryos (stage 18), the neural plate and notochord were split regionally to construct a fistula that appeared to be the ectopic neurenteric canal. Following this procedure, the embryonic development was traced morphologically and histologically. RESULTS: Following the incubation and breeding period, split cord malformation was observed in some animals. Scoliosis, spina bifida, vertebral anomaly and subcutaneous manifestations were also observed with SCMs. CONCLUSIONS: The observations made in these experimentally induced SCMs are consistent with the findings in human SCMs. We report an experimental animal model of split cord malformation, in which double spinal cords were developed in the spinal canal. In addition, we examined the embryogenesis of SCMs. This study indicates that SCMs may arise through a process of dorsal midline fistula of the neural plate.     

Fanconi anemia and beta c deficiency-associated pulmonary alveolar proteinosis as two hereditary diseases of childhood which are potentially curable by stem cell gene therapy but require different therapeutic approaches.

Fanconi anemia (FANC) and pulmonary alveolar proteinosis associated with deficiency of the beta-chain common to the GM-CSF/IL3/IL5 receptors (beta c-PAP) are rare inherited disorders of childhood or adolescence. Hematopoietic stem cell gene therapy aiming at reintroducing the wildtype cDNA as a new concept for the treatment of hereditary diseases may be applicable to FANC and PAP, as both disorders can be successfully treated by allogeneic stem cell transplantation. However, there are important distinctions to be made between the two diseases: FANC seems to be a disorder with functional stem cell deficiency. Thus, introduction of the wildtype cDNA should provide an in vivo growth advantage to genetically corrected stem cells so that corrected cells and their progeny may expand in vivo and slowly repopulate the entire hematopoietic system. In beta c-PAP, the defect has no major impact on proliferation or differentiation of stem cells. Therefore, introduction of the wildtype gene will probably not provide any selective growth advantage and the percentage of corrected cells in the hematopoietic compartment depend on the percentage of stem cells initially transduced as the current technology only allows for transduction of stem cells with low efficiency. The introduction of a second selectable cDNA into the vector might be used to provide selective growth for modified cells and thus overcome a low gene transfer efficiency of stem cells. The correction of rare monogenetic diseases may serve as a model for gene therapy prior to attempts to treat more common and complex polygenetic diseases. The studies outlined here will be helpful envisioning new treatment strategies for other inherited monogenetic diseases such as mucopolysaccharidosis, Gauchers disease or adrenoleukodystrophy.     

Stem cell and regenerative science applications in the development of bioengineering of renal tissue

A rising number of patients with acute and chronic renal failure worldwide have created urgency for clinicians and investigators to search out alternative therapies other than chronic renal dialysis and/or organ transplantation. This review focuses on the recent achievements in this area, and discusses the various approaches in the development of bioengineering of renal tissue including recent discoveries in the field of regenerative medicine research and stem cells. A variety of stem cells, ranging from embryonic, bone marrow, endogenous, and amniotic fluid, have been investigated and may prove useful as novel alternatives for organ regeneration both in vitro and in vivo. Tissue engineering, developmental biology, and therapeutic cloning techniques have significantly contributed to our understanding of some of the molecular mechanisms involved in renal regeneration and have demonstrated that renal tissue can be generated de novo with similar physiologic functions as native tissue. Ultimately all of these emerging technologies may provide viable therapeutic options for regenerative medicine applications focused on the bioengineering of renal tissue for the future.     

Prospects and challenges of reprogrammed cells in hematology and oncology

Induced pluripotent stem cells (iPSCs) have emerged as a promising basis for modeling pediatric genetic disorders, allowing the derivation, study, and genetic correction of disease and patient-specific cell lines in vitro. Similar to embryonic stem cells (ESCs), iPSCs are capable of unlimited in vitro expansion and derivation of many cell types, including hematopoietic stem cells (HSCs). These may not only allow large scale screenings to develop therapeutic compounds, but also help to overcome cross-species barriers of genetically engineered animal models, which do not adequately recapitulate the associated human phenotype. Here, we review the current state and emerging developments of iPSC research, which can be exploited as a tool in modeling pediatric hematopoietic disorders and could lead to new clinical applications in gene and cell therapies.     

Zebrafish as a developmental model organism for pediatric research

Zebrafish has many advantages as a model of human pediatric research. Given the physical and ethical problems with performing experiments on human patients, biomedical research has focused on using model organisms to study biologic processes conserved between humans and lower vertebrates. The most common model organisms are small mammals, usually rats and mice. Although these models have significant advantages, they are also expensive to maintain, difficult to manipulate embryonically, and limited for large-scale genetic studies. The zebrafish model nicely complements these deficiencies in mammalian experimental models. The low cost, small size, and external development of zebrafish make it an excellent model for vertebrate development biology. Techniques for large-scale genome mutagenesis and gene mapping, transgenesis, protein overexpression or knockdown, cell transplantation and chimeric embryo analysis, and chemical screens have immeasurably increased the power of this model organism. It is now possible to rapidly determine the developmental function of a gene of interest in vivo, and then identify genetic and chemical modifiers of the processes involved. Discoveries made in zebrafish can be further validated in mammals. With novel technologies being regularly developed, the zebrafish is poised to significantly improve our understanding of vertebrate development under normal and pathologic conditions.     

Routes to regenerating islet cells: stem cells and other biological therapies for type 1 diabetes

Abstract:  New biological therapies for type 1 diabetes are emerging from the forefront of stem cell and islet cell biology. Basic research in animal models has uncovered a variety of mechanisms by which natural regeneration of pancreatic islet cells occurs, despite the underlying autoimmune defect. Two mechanisms – in particular, β-islet cell proliferation and stem cell differentiation – can be harnessed in innovative ways in order to regenerate islets lost to disease. This review provides a background on stem cells and describes a range of potential biological therapies for type 1 diabetes, including the use of adult stem cells from the spleen, an organ not previously considered a source of pancreatic stem cells. Stem cells of the spleen have been demonstrated to home to the pancreas, where they mature into fully functional islet cells responsible for restoring normoglycemia. If the underlying autoimmune defect can be eradicated, stem cells of the spleen, as well as related strategies, can be used in order to regrow islets destroyed by type 1 diabetes.     

Engineered human cardiac tissue

The human heart is the first organ to develop during embryogenesis and is arguably the most essential organ for life. However, after birth, the heart has very little capacity to repair malformations such as congenital heart defects or to regenerate after an injury such as myocardial infarction. Cardiac tissue engineering addresses the need for a therapeutic biologic implant to restore cardiac structure and muscle mass. This review highlights current research in cardiac tissue engineering that uses human cardiomyocytes derived from embryonic stem cells. Other human cell sources are discussed because future human therapies will benefit from novel techniques using human-induced pluripotent stem cells and cardiomyocytes derived from direct reprogramming of somatic cells. Furthermore, this review examines the main approaches to creating engineered cardiac tissue with synthetic scaffolds, natural scaffolds, or no exogenous scaffold (i.e., “scaffold free”). The choice of scaffold and cells ultimately depends on the goals of the therapy, so the review considers how congenital heart defects define the design parameters for cardiac tissue engineering needed for surgical repair in pediatric cardiac patients.     

Innovative tools in the individualized medical therapy for children with heart muscle disease

Individualized medical therapy for children with heart muscle disease remains a challenge. Two innovative tools, physiologically based pharmacokinetic modeling and stem cell technology, have the potential to address these challenges. In this review, these technologies are introduced to provide the reader with a general conceptual overview and how they can help in guiding individualized treatment.In recent years, there has been an explosion of knowledge about how the genetic makeup of patients governs their response to medical treatment. For heart failure patients or patients after heart transplantation, drugs such as ACE-inhibitors, AT1-receptors, β-adrenergic receptor blockers, aldosterone antagonists as well as immunosuppressives might be candidates for pharmacogenetic-tailored drug therapy. To maximize the advantage for the individual patient, novel treatment approaches integrate pharmacogenetic information into physiologically-based pharmacokinetic models to predict drug absorption, distribution, metabolism and elimination (ADME) in the individual patient. How these models are built and how they can help in guiding individual treatment protocols will be discussed and several examples presented.Although population-based gene variant studies provide an important first step towards applying a pharmacogenomic approach to heart failure medications in children, the true connection between any gene variant and its effect on drug efficacy and toxicity in the clinical setting requires additional proof. Given the difficulty in transitioning past genome-wide association study (GWAS) data into clinical practice, it is important that each candidate gene variant be validated using a suitable model system. In the past, these model systems were limited to whole animal studies, where data interpretation was complicated by species differences. The lack of a human cardiomyocyte cell line had similarly prevented the translation of many in vitro studies to clinical practice. Recent advances in stem cell technology, including the generation of human cardiomyocyte cell lines from induced pluripotent stem cells (hiPSCs), provide a new platform to test drugs for both toxicity and therapeutic benefit.     

Special considerations for the health care of adolescents with chronic illnesses

While issues of independence, sexuality, and identity are important for all adolescents, they become of particular concern for chronically ill teenagers because of the interaction of rapid developmental change in these areas with the stresses of chronic illness. Unlike adults with chronic diseases who often need to be rehabilitated so that they can function independently again and resume their sexual lives, adolescents need to be habilitated; they have no prior experience to draw on. Chronically ill children can be sheltered and protected from many stresses by their families, but as they move into the adolescent years, they must be allowed to gradually take over responsibility for their actions. This takes practice, and some mistakes are inevitable. In addition, teenagers with chronic illnesses deserve assistance to help them maximize their strengths and develop a positive self-identity. Health professionals have a significant role to play in encouraging independence, preventing adverse consequences of sexual behavior, and enhancing the self-image of their chronically ill adolescent patients.     

利用人胚胎干细胞和人羊水干细胞的神经分化模型建立体外神经毒性测试的实验研究

目的 许多药物具有神经毒性,尤其是对于儿童的影响更大.目前常用的药物体内毒性实验既耗时又昂贵.人胚胎干细胞和人羊水干细胞的神经分化有望建立一种理想的用于评价药物神经毒性的体外评估系统.此项研究旨在利用红藻氨酸的神经毒性验证此系统的可行性.方法 单层贴壁状态下,人胚胎干细胞和人羊水干细胞在化学成分明确的诱导条件下向神经细胞诱导.这些细胞经神经细胞特异性的抗体染色证实其特性.诱导得到的神经细胞在不同浓度红藻氨酸的培养液中进行培养和扩增,每代细胞进行计数,绘制细胞的生长曲线.结果 人胚胎干细胞和人羊水干细胞均可被高效地诱导为神经细胞;人胚胎干细胞的神经诱导效率高于人羊水干细胞;红藻氨酸对诱导得到的神经细胞具有毒性,其浓度与毒性呈正相关.结论 人胚胎干细胞和人羊水干细胞的体外神经分化可作为用于评价药物神经毒性的体外评估系统.

Abstract：

Objective A lot of drugs have side effects on the central nerves system. Especially in children. In vivo neurotoxicity tests are time-consuming and expensive. The neural differentiation of human embryonic stem cells and amniotic fluid stem cells provides all ideal in vitro system that Can be applied to evaluate neurotoxicity of drugs. This study was to try to establish such a system. The kainie acid was selected to test the neurotoxicity. Methods The human embryonic stem cells and amniotic fluid stem cells were indueed to differentiate into neural cells by a chemically defined neural induction medium. The induced neural cells were propagated in the presence of basic fibroblast growth factor. Immunocytochemical staining Was applied to confirm these cells' neural identity. The induced cells were propagated under different concentration of kainic acid, then the gosh curve were made based on the cell numbers. Results Both of the human embryonic stem cells and amniotic fluid stem cells could be efficiently induced to be differentiated into neural cells. The neural differentiation efficiency of human embryonic stem cells is higher than that of human amniotic fluid stem cells. The kainic acid has neurotoxieity to the indueed neural cells. Conclusions The neural differentiation of human embryonic stem cells and amniotic fluid stem cells were proved to provide a rapid and convenient approach for estimating the neurotoxlcity of drugs.     

Parental questions about developmental coordination disorder: A synopsis of current evidence

In recent years, knowledge about developmental coordination disorder (DCD) has accumulated very rapidly. Considerable progress has been made in the understanding of DCD, but recent studies have not been compiled in a way that makes them easily accessible to practicing paediatricians. In the present paper, the literature is reviewed and organized around the questions commonly raised by parents of children with DCD when they meet with their paediatrician. Parents express concern and seek information about their child’s movement difficulties. They want to know what causes their child’s lack of coordination and whether DCD is the correct diagnosis. Are other developmental disorders involved? What can they do to help their child’s daily frustrations? The present review addresses frequently asked questions through a critical appraisal of current research literature. Paediatricians who are familiar with the research evidence will be better able to recognize these children and to share information with parents.     

Current concepts in stem cell research

In the last few years, advances in stem cell research have opened up new horizons in the treatment of human diseases and in regenerative medicine. It is not unusual to find news on stem cell research in newspapers and other media. This review describes some basic concepts in research needed to understand the medical literature on stem cells and to provide the information and bibliography necessary to be up to date in one of the subjects that has generated the greatest number of publications in the last few years.     

Optimizing neurodevelopmental outcomes after prematurity: lessons in neuroprotection and early intervention

In recent decades, advances in maternal-fetal, obstetrics, and neonatal medicine have led to the increased survival of preterm infants. Very preterm infants (<32 weeks gestation), who comprise a small fraction (1.4%) of all neonates, have had dramatic increases in their survival. In addition, late preterm infants (33-36 weeks gestation) are a growing population of all preterm births and may include over 10% of all births. Both populations experience ongoing and significant challenges once they are discharged from the neonatal intensive care unit (NICU), including medical, nutritional, and developmental issues. Similarly, preterm infants may experience ongoing challenges once they enter school. As a result, clinicians should be aware of the unique neurodevelopmental issues that affect this population of children, including what they experience at different developmental stages. This review will describe how selected neonatal interventions impact on very preterm and late preterm infants. In addition, we will discuss the developmental and functional components of school readiness in very preterm and late preterm infants, using the International Classification of Functioning, Disability, and Health (ICF) as a framework for health, enablement, disability, and participation. This framework allows us to describe children's strengths and challenges across body structure and body function, activities, and social roles in the context of child and family supports. We will explicitly describe the role of physicians and health professional teams in providing ongoing support and coordination of care throughout childhood for preterm infants who have experienced neonatal intensive care.