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KEY POINTS: Chitosan is a promising drug delivery vector for therapeutics owing to its biocompatibility. Once crosslinked with chitosan, prolonged drug release was noted regardless of hydrophilicity. Hydrophilic drugs may require different strategies to obtain a sustained release profile.
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A recent decision reveals how a New Zealand's disciplinary tribunal promoted justice for an unwell lawyer in a case of professional misconduct. In 2023, the Lawyers and Conveyancers Disciplinary Tribunal (LCDT) applied a 'merciful approach' when assessing the lawyer's misconduct and health issues. In Auckland Standards Committee 3 v Ms W [2023], the LCDT discussed the impacts of reproductive treatment in relation to the practitioner's conduct. This decision is the foundation to compare the disciplinary regime for legal and health practitioners in New Zealand. The article outlines New Zealand's framework for discipline of lawyers, noting the absence of a health pathway. The article discusses opportunities to resolve cases involving impaired lawyers outside the disciplinary system, including benefits and disadvantages of mandatory reporting. While focusing on the legal profession, the discussion is relevant to other professions and examines health-promoting regulatory strategies from other jurisdictions.
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Repeated paternal preconception exposure to Δ9-tetrahydrocannabinol (Δ9-THC) alone or together with the other constituents in a cannabis extract has been shown in our earlier studies in rats to cause significant neurobehavioral impairment in their offspring. In the current study, we compared the effects of daily cannabis extract (CE) exposure to cannabis on two consecutive days per week, modeling weekend cannabis use in human. The CE contained Δ9-THC as well as cannabidiol and cannabinol. We also extended the investigation of the study to cross-generational effects of grand-paternal cannabis exposure on the F2 generation and included testing the effects of paternal cannabis exposure on responding for opiate self-administration in F1 and F2 generation offspring. We replicated the findings of neurobehavioral impairment in F1 offspring of male rats exposed to cannabis extract containing 4â¯mg/kg/day of Δ9-THC daily for four weeks prior to mating with drug naïve females. The 4-week cannabis extract exposure caused a significant decrease in weight gain in the male rats exposed daily. In contrast, their offspring showed significantly greater body weights and anogenital distances (AGD) in the third to fourth weeks after birth. The behavioral effects seen in the F1 generation were increased habituation of locomotor activity in the figure-8 maze in female offspring and increased lever pressing for the opiate drug remifentanil in male offspring. The F2 generation showed significantly impaired negative geotaxis and an elimination of the typical sex-difference in locomotor activity, with effects not seen in the F1 generation. This study shows that daily paternal cannabis exposure for four weeks prior to mating causes significant neurobehavioral impairment in the F1 and F2 offspring. Intermittent exposure on two consecutive days per week for four weeks caused comparable neurobehavioral impairment. In sum, there should be concern about paternal as well as maternal exposure to cannabis concerning neurobehavioral development of their offspring.
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Dronabinol , Exposición Paterna , Animales , Masculino , Femenino , Exposición Paterna/efectos adversos , Ratas , Dronabinol/administración & dosificación , Dronabinol/toxicidad , Embarazo , Cannabis , Conducta Animal/efectos de los fármacos , Autoadministración , Peso Corporal/efectos de los fármacosRESUMEN
OBJECTIVES: Previously, we developed a novel double-coated sinus stent containing ciprofloxacin (inner layer) and azithromycin (outer layer) (CASS), but released drug concentrations were found to be insufficient for clinical usage. Our objectives are to improve drug release of CASS and assess safety and pharmacokinetics in rabbits. METHODS: Dip coating was used to create the CASS with 2 mg ciprofloxacin and 5 mg azithromycin. A uniformed double coating was assessed with scanning electron microscopy (SEM), and the release patterns of both drugs and lactate dehydrogenase (LDH) assay were evaluated over 14 days in vitro. Safety, tolerability, and pharmacokinetics of the CASS were tested in rabbits through insertion into the maxillary sinus and evaluated with nasal endoscopy, CT scans, histology, blood counts and chemistries, and in vivo drug release. RESULTS: SEM confirmed the uniformity of the dual coating of ciprofloxacin and azithromycin, and thickness (µm) was found to be 14.7 ± 2.4 and 28.1 ± 4.6, respectively. The inner coated ciprofloxacin showed a sustained release over 14 days (release %) when soaked in saline solution (day 7, 86.2 ± 3.4 vs. day 14,99.2 ± 5.1). In vivo analysis showed that after 12 days, 78.92 ± 7.67% of CP and 84.12 ± 0.45% of AZ were released into the sinus. There were no significant differences in body weight, white blood cell counts, and radiographic changes before and after CASS placement. No significant histological changes were observed compared to the contralateral control side. CONCLUSION: Findings suggest that the CASS is an effective method for delivering therapeutic levels of antibiotics. Further studies are needed to validate efficacy in a preclinical sinusitis model. LEVEL OF EVIDENCE: N/A Laryngoscope, 134:3953-3959, 2024.
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Antibacterianos , Azitromicina , Ciprofloxacina , Rinosinusitis , Animales , Conejos , Antibacterianos/administración & dosificación , Antibacterianos/efectos adversos , Antibacterianos/farmacocinética , Azitromicina/administración & dosificación , Azitromicina/efectos adversos , Azitromicina/farmacocinética , Enfermedad Crónica , Ciprofloxacina/administración & dosificación , Ciprofloxacina/efectos adversos , Ciprofloxacina/farmacocinética , Modelos Animales de Enfermedad , Stents Liberadores de Fármacos/efectos adversos , Seno Maxilar/cirugía , Seno Maxilar/diagnóstico por imagen , Microscopía Electrónica de Rastreo , Rinosinusitis/tratamiento farmacológicoRESUMEN
INTRODUCTION: Cystic fibrosis (CF) airway disease is characterized by thick mucus and impaired mucociliary transport (MCT). Loss of functional cystic fibrosis transmembrane receptor (CFTR) leads to acidification and oxidation of airway surface mucus. Replacing bicarbonate (HCO3 - ) topically fails due to rapid reabsorption and neutralization, while the scavenging antioxidant, glutathione sulfhydryl (GSH), is also rapidly degraded. The objective of this study is to investigate GSH/NaHCO3 nanoparticles as novel strategy for CF airway disease. METHODS: GSH/NaHCO3 poly (lactic-co-glycolic acid) nanoparticles were tested on primary CF (F508del/F508del) epithelial cultures to evaluate dose-release curves, surface pH, toxicity, and MCT indices using micro-optical coherence tomography. In vivo tests were performed in three rabbits to assess safety and toxicity. After 1 week of daily injections, histopathology, computed tomography (CT), and blood chemistries were performed and compared to three controls. Fluorescent nanoparticles were injected into a rabbit with maxillary sinusitis and explants visualized with confocal microscopy. RESULTS: Sustained release of GSH and HCO3 - with no cellular toxicity was observed over 2 weeks. Apical surface pH gradually increased from 6.54 ± 0.13 (baseline) to 7.07 ± 0.10 (24 h) (p < 0.001) and 6.87 ± 0.05 at 14 days (p < 0.001). MCT, ciliary beat frequency, and periciliary liquid were significantly increased. When injected into the maxillary sinuses of rabbits, there were no changes to histology, CT, or blood chemistries. Nanoparticles penetrated rabbit sinusitis mucus on confocal microscopy. CONCLUSION: Findings suggest that GSH/NaHCO3 - nanoparticles are a promising treatment option for viscous mucus in CF and other respiratory diseases of mucus obstruction such as chronic rhinosinusitis.
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AIM: This commentary presents practical and evidenced based guidelines for the development and delivery of real-time online training workshops aimed at rural health professionals. CONTEXT: Online learning is increasingly being used as an avenue for delivering education, particularly to rural and remote sites where barriers persist in upskilling health workers. Further, online learning has become essential during the coronavirus disease 2019 (COVID-19) pandemic. In response to the Australian 2020 COVID-19 social distancing requirements, our team rapidly transformed face-to-face educational workshops into an online format, to deliver over 20 workshops to more than 150 multidisciplinary staff across our large rural district. APPROACH: There are no published guidelines regarding the conversion of face-to-face education programs into an online format within health care. We conducted a review of the literature regarding the implementation of online education programs. Three broad categories of evidence were identified: participant qualities, content development and content deliverance. CONCLUSION: We present a set of practical and evidenced based recommendations, which will enhance live online workshops for a rural health workforce. These recommendations are derived both from published literature and our experience delivering our workshops. We argue that rural health professionals and organisations need relevant, up-to-date practical guidelines and more institutional support and training focused on creating and implementing live online educational programs in rural Australia.
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COVID-19 , Educación a Distancia , Servicios de Salud Rural , Humanos , Australia , Salud Rural , Fuerza Laboral en SaludRESUMEN
This study investigates the rates and types of criminal convictions encountered by New Zealand's Health Practitioners Disciplinary Tribunal (HPDT) over a 15-year period. Criminal convictions appeared in 24% (n = 101) of cases, with male practitioners (p < 0.01) and pharmacists (p < 0.05) being significantly over-represented. The most frequent types of convictions included crimes against rights of property (33.6%), sexual/morality/decency crimes (21.9%) and misuse of drugs (8.4%). Criminal behaviour settings were evenly split between personal and professional life for medical practitioners (56.5% professional life) and nurses (56.5% professional life) but disproportionately in professional life (85%) for pharmacists. Criminal conviction cases were significantly more likely to result in registration cancellation (p < 0.001) and practice suspensions (p < 0.05) when compared with non-criminal cases, although fewer fines were ordered (p < 0.001). Profession-specific risk factors, alongside how to rehabilitate members of the subgroup who may later seek to renew their practice are areas for further research, are discussed.
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Criminales , Crimen , Conducta Criminal , Personal de Salud , Humanos , Masculino , Nueva ZelandaRESUMEN
Disciplinary tribunals are deserving of review, in the interests of fairness, transparency and educational value for key stakeholders. New Zealand's Health Practitioners Disciplinary Tribunal (HPDT) determines whether registered health practitioners have engaged in misconduct that warrants discipline. The current study considers patterns regarding HPDT hearing processes and outcomes (2004-2020) (420 decisions), expanding knowledge from a previous analysis of HPDT decisions (2004-2014). The findings suggest that the HPDT has largely upheld its goal of consistency. However, shifts over time have included a reduced rate of appeals, and changing patterns for both the grounds for discipline and penalties applied. Differences in HPDT processes and penalties between medical practitioners, nurses and pharmacists were largely accounted for by the factors of practitioner attendance and legal representation at the hearing. This study contributes to understanding who transgresses, how they transgress and the penalties imposed. Such insights may be applied preventively for the benefit of all stakeholders.
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Personal de Salud , Humanos , Nueva ZelandaRESUMEN
In type 1 diabetes, a renewable source of human pancreatic ß cells, in particular from human induced pluripotent stem cell (hiPSC) origin, would greatly benefit cell therapy. Earlier work showed that pancreatic progenitors differentiated from human embryonic stem cells in vitro can further mature to become glucose responsive following macroencapsulation and transplantation in mice. Here we took a similar approach optimizing the generation of pancreatic progenitors from hiPSCs. This work demonstrates that hiPSCs differentiated to pancreatic endoderm in vitro can be efficiently and robustly generated under large-scale conditions. The hiPSC-derived pancreatic endoderm cells (HiPECs) can further differentiate into glucose-responsive islet-like cells following macroencapsulation and in vivo implantation. The HiPECs can protect mice from streptozotocin-induced hyperglycemia and maintain normal glucose homeostasis and equilibrated plasma glucose concentrations at levels similar to the human set point. These results further validate the potential use of hiPSC-derived islet cells for application in clinical settings.
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Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Experimental/terapia , Células Madre Pluripotentes Inducidas/citología , Células Secretoras de Insulina/citología , Células Secretoras de Insulina/metabolismo , Trasplante de Células Madre , Animales , Biomarcadores , Glucemia , Péptido C/sangre , Diferenciación Celular , Diabetes Mellitus Experimental/sangre , Diabetes Mellitus Experimental/etiología , Modelos Animales de Enfermedad , Endodermo/citología , Técnica del Anticuerpo Fluorescente , Humanos , Hiperglucemia/etiología , Hiperglucemia/metabolismo , Hiperglucemia/terapia , Inmunofenotipificación , Insulina/biosíntesis , Ratones , Modelos Biológicos , Resultado del TratamientoRESUMEN
The KRAS-variant is a biologically functional, microRNA binding site variant, which predicts increased cancer risk especially for women. Because external exposures, such as chemotherapy, differentially impact the effect of this mutation, we evaluated the association of estrogen exposures, breast cancer (BC) risk and tumor biology in women with the KRAS-variant. Women with BC (n = 1712), the subset with the KRAS-variant (n = 286) and KRAS-variant unaffected controls (n = 80) were evaluated, and hormonal exposures, KRAS-variant status, and pathology were compared. The impact of estrogen withdrawal on transformation of isogenic normal breast cell lines with or without the KRAS-variant was studied. Finally, the association and presentation characteristics of the KRAS-variant and multiple primary breast cancer (MPBC) were evaluated. KRAS-variant BC patients were more likely to have ovarian removal pre-BC diagnosis than non-variant BC patients (p = 0.033). In addition, KRAS-variant BC patients also appeared to have a lower estrogen state than KRAS-variant unaffected controls, with a lower BMI (P < 0.001). Finally, hormone replacement therapy (HRT) discontinuation in KRAS-variant patients was associated with a diagnosis of triple negative BC (P < 0.001). Biologically confirming our clinical findings, acute estrogen withdrawal led to oncogenic transformation in KRAS-variant positive isogenic cell lines. Finally, KRAS-variant BC patients had greater than an 11-fold increased risk of presenting with MPBC compared to non-variant patients (45.39% vs 6.78%, OR 11.44 [3.42-37.87], P < 0.001). Thus, estrogen withdrawal and a low estrogen state appear to increase BC risk and to predict aggressive tumor biology in women with the KRAS-variant, who are also significantly more likely to present with multiple primary breast cancer.
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Neoplasias de la Mama/genética , Neoplasias de la Mama/metabolismo , Estrógenos/metabolismo , Predisposición Genética a la Enfermedad/genética , Variación Genética/genética , Proteínas Proto-Oncogénicas p21(ras)/genética , Línea Celular Tumoral , Terapia de Reemplazo de Estrógeno/tendencias , Estrógenos/deficiencia , Femenino , Humanos , Factores de Riesgo , Síndrome de Abstinencia a Sustancias/genética , Síndrome de Abstinencia a Sustancias/metabolismoRESUMEN
Embryonic development is characterized by dynamic changes in gene expression, yet the role of chromatin remodeling in these cellular transitions remains elusive. To address this question, we profiled the transcriptome and select chromatin modifications at defined stages during pancreatic endocrine differentiation of human embryonic stem cells. We identify removal of Polycomb group (PcG)-mediated repression on stage-specific genes as a key mechanism for the induction of developmental regulators. Furthermore, we discover that silencing of transitory genes during lineage progression associates with reinstatement of PcG-dependent repression. Significantly, in vivo- but not in vitro-differentiated endocrine cells exhibit close similarity to primary human islets in regard to transcriptome and chromatin structure. We further demonstrate that endocrine cells produced in vitro do not fully eliminate PcG-mediated repression on endocrine-specific genes, probably contributing to their malfunction. These studies reveal dynamic chromatin remodeling during developmental lineage progression and identify possible strategies for improving cell differentiation in culture.
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Ensamble y Desensamble de Cromatina/fisiología , Células Madre Embrionarias/citología , Páncreas/citología , Proteínas del Grupo Polycomb/metabolismo , Animales , Diferenciación Celular/genética , Diferenciación Celular/fisiología , Ensamble y Desensamble de Cromatina/genética , Células Madre Embrionarias/metabolismo , Células Endocrinas/citología , Células Endocrinas/metabolismo , Endodermo/citología , Endodermo/metabolismo , Humanos , Ratones , Proteínas del Grupo Polycomb/genéticaRESUMEN
The peptide hormone Urocortin 3 (Ucn 3) is abundantly and exclusively expressed in mouse pancreatic beta cells where it regulates insulin secretion. Here we demonstrate that Ucn 3 first appears at embryonic day (E) 17.5 and, from approximately postnatal day (p) 7 and onwards throughout adult life, becomes a unifying and exclusive feature of mouse beta cells. These observations identify Ucn 3 as a potential beta cell maturation marker. To determine whether Ucn 3 is similarly restricted to beta cells in humans, we conducted comprehensive immunohistochemistry and gene expression experiments on macaque and human pancreas and sorted primary human islet cells. This revealed that Ucn 3 is not restricted to the beta cell lineage in primates, but is also expressed in alpha cells. To substantiate these findings, we analyzed human embryonic stem cell (hESC)-derived pancreatic endoderm that differentiates into mature endocrine cells upon engraftment in mice. Ucn 3 expression in hESC-derived grafts increased robustly upon differentiation into mature endocrine cells and localized to both alpha and beta cells. Collectively, these observations confirm that Ucn 3 is expressed in adult beta cells in both mouse and human and appears late in beta cell differentiation. Expression of Pdx1, Nkx6.1 and PC1/3 in hESC-derived Ucn 3(+) beta cells supports this. However, the expression of Ucn 3 in primary and hESC-derived alpha cells demonstrates that human Ucn 3 is not exclusive to the beta cell lineage but is a general marker for both the alpha and beta cell lineages. Ucn 3(+) hESC-derived alpha cells do not express Nkx6.1, Pdx1 or PC1/3 in agreement with the presence of a separate population of Ucn 3(+) alpha cells. Our study highlights important species differences in Ucn 3 expression, which have implications for its utility as a marker to identify mature beta cells in (re)programming strategies.
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Células Madre Embrionarias/metabolismo , Células Secretoras de Glucagón/metabolismo , Células Secretoras de Insulina/metabolismo , Urocortinas/metabolismo , Animales , Diferenciación Celular/genética , Linaje de la Célula , Células Madre Embrionarias/citología , Expresión Génica , Células Secretoras de Glucagón/citología , Proteínas de Homeodominio/genética , Proteínas de Homeodominio/metabolismo , Humanos , Inmunohistoquímica/métodos , Células Secretoras de Insulina/citología , Islotes Pancreáticos/citología , Islotes Pancreáticos/metabolismo , Ratones , Transactivadores/genética , Transactivadores/metabolismo , Urocortinas/genéticaRESUMEN
Development of a human embryonic stem cell (hESC)-based therapy for type 1 diabetes will require the translation of proof-of-principle concepts into a scalable, controlled, and regulated cell manufacturing process. We have previously demonstrated that hESC can be directed to differentiate into pancreatic progenitors that mature into functional glucose-responsive, insulin-secreting cells in vivo. In this study we describe hESC expansion and banking methods and a suspension-based differentiation system, which together underpin an integrated scalable manufacturing process for producing pancreatic progenitors. This system has been optimized for the CyT49 cell line. Accordingly, qualified large-scale single-cell master and working cGMP cell banks of CyT49 have been generated to provide a virtually unlimited starting resource for manufacturing. Upon thaw from these banks, we expanded CyT49 for two weeks in an adherent culture format that achieves 50-100 fold expansion per week. Undifferentiated CyT49 were then aggregated into clusters in dynamic rotational suspension culture, followed by differentiation en masse for two weeks with a four-stage protocol. Numerous scaled differentiation runs generated reproducible and defined population compositions highly enriched for pancreatic cell lineages, as shown by examining mRNA expression at each stage of differentiation and flow cytometry of the final population. Islet-like tissue containing glucose-responsive, insulin-secreting cells was generated upon implantation into mice. By four- to five-months post-engraftment, mature neo-pancreatic tissue was sufficient to protect against streptozotocin (STZ)-induced hyperglycemia. In summary, we have developed a tractable manufacturing process for the generation of functional pancreatic progenitors from hESC on a scale amenable to clinical entry.
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Técnicas de Cultivo Celular por Lotes/métodos , Diferenciación Celular/fisiología , Diabetes Mellitus Tipo 1/terapia , Células Madre Embrionarias/citología , Células Madre Embrionarias/trasplante , Células Secretoras de Insulina/citología , Análisis de Varianza , Animales , Criopreservación/métodos , Células Madre Embrionarias/fisiología , Citometría de Flujo , Técnica del Anticuerpo Fluorescente , Perfilación de la Expresión Génica , Humanos , Masculino , Ratones , Ratones SCID , EstreptozocinaRESUMEN
Using a flow cytometry-based screen of commercial antibodies, we have identified cell-surface markers for the separation of pancreatic cell types derived from human embryonic stem (hES) cells. We show enrichment of pancreatic endoderm cells using CD142 and of endocrine cells using CD200 and CD318. After transplantation into mice, enriched pancreatic endoderm cells give rise to all the pancreatic lineages, including functional insulin-producing cells, demonstrating that they are pancreatic progenitors. In contrast, implanted, enriched polyhormonal endocrine cells principally give rise to glucagon cells. These antibodies will aid investigations that use pancreatic cells generated from pluripotent stem cells to study diabetes and pancreas biology.
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Antígenos CD/metabolismo , Biomarcadores/metabolismo , Separación Celular/métodos , Células Madre Embrionarias/citología , Páncreas/citología , Animales , Anticuerpos/metabolismo , Células Cultivadas , Células Madre Embrionarias/metabolismo , Endodermo/citología , Citometría de Flujo , Humanos , Ratones , Ratones SCID , Microscopía Fluorescente , Trasplante HeterólogoRESUMEN
The development of the cardiovascular system is a highly dynamic process dependent on multiple signaling pathways regulating proliferation, differentiation, migration, cell-cell and cell-matrix interactions. To characterize cell and tissue dynamics during the formation of the cardiovascular system in mice, we generated a novel transgenic mouse line, Tg(Flk1::myr-mCherry), in which endothelial cell membranes are brightly labeled with mCherry, a red fluorescent protein. Tg(Flk1::myr-mCherry) mice are viable, fertile, and do not exhibit any developmental abnormalities. High levels of mCherry are expressed in the embryonic endothelium and endocardium, and expression is also observed in capillaries in adult animals. Targeting of the fluorescent protein to the cell membrane allows for subcellular imaging and cell tracking. By acquiring confocal time lapses of live embryos cultured on the microscope stage, we demonstrate that the newly generated transgenic model beautifully highlights the sprouting behaviors of endothelial cells during vascular plexus formation. We have also used embryos from this line to imaging the endocardium in the beating embryonic mouse heart, showing that Tg(Flk1::myr-mCherry) mice are suitable for the characterization of cardio dynamics. Furthermore, when combined with the previously described Tg(Flk1::H2B-EYFP) line, cell number in addition to cell architecture is revealed, making it possible to determine how individual endothelial cells contribute to the structure of the vessel.
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Vasos Sanguíneos/embriología , Sistema Cardiovascular/embriología , Membrana Celular/metabolismo , Embrión de Mamíferos/irrigación sanguínea , Células Endoteliales/metabolismo , Proteínas Luminiscentes/metabolismo , Animales , Vasos Sanguíneos/metabolismo , Sistema Cardiovascular/metabolismo , Núcleo Celular , Embrión de Mamíferos/metabolismo , Endocardio , Endotelio Vascular , Células HeLa , Humanos , Ratones , Ratones Transgénicos , Receptor 2 de Factores de Crecimiento Endotelial Vascular/fisiología , Proteína Fluorescente RojaRESUMEN
Development of a cell therapy for diabetes would be greatly aided by a renewable supply of human beta-cells. Here we show that pancreatic endoderm derived from human embryonic stem (hES) cells efficiently generates glucose-responsive endocrine cells after implantation into mice. Upon glucose stimulation of the implanted mice, human insulin and C-peptide are detected in sera at levels similar to those of mice transplanted with approximately 3,000 human islets. Moreover, the insulin-expressing cells generated after engraftment exhibit many properties of functional beta-cells, including expression of critical beta-cell transcription factors, appropriate processing of proinsulin and the presence of mature endocrine secretory granules. Finally, in a test of therapeutic potential, we demonstrate that implantation of hES cell-derived pancreatic endoderm protects against streptozotocin-induced hyperglycemia. Together, these data provide definitive evidence that hES cells are competent to generate glucose-responsive, insulin-secreting cells.
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Técnicas de Cultivo de Célula/tendencias , Células Madre Embrionarias/citología , Glucosa/metabolismo , Células Secretoras de Insulina/citología , Células Secretoras de Insulina/metabolismo , Insulina/metabolismo , Ingeniería de Tejidos/tendencias , Animales , Diferenciación Celular , Proliferación Celular , Células Cultivadas , Células Madre Embrionarias/metabolismo , Células Madre Embrionarias/trasplante , Endodermo/citología , Endodermo/metabolismo , Humanos , Células Secretoras de Insulina/trasplante , Ratones , Páncreas Artificial/tendenciasRESUMEN
Of paramount importance for the development of cell therapies to treat diabetes is the production of sufficient numbers of pancreatic endocrine cells that function similarly to primary islets. We have developed a differentiation process that converts human embryonic stem (hES) cells to endocrine cells capable of synthesizing the pancreatic hormones insulin, glucagon, somatostatin, pancreatic polypeptide and ghrelin. This process mimics in vivo pancreatic organogenesis by directing cells through stages resembling definitive endoderm, gut-tube endoderm, pancreatic endoderm and endocrine precursor--en route to cells that express endocrine hormones. The hES cell-derived insulin-expressing cells have an insulin content approaching that of adult islets. Similar to fetal beta-cells, they release C-peptide in response to multiple secretory stimuli, but only minimally to glucose. Production of these hES cell-derived endocrine cells may represent a critical step in the development of a renewable source of cells for diabetes cell therapy.
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Diferenciación Celular/fisiología , Células Madre Embrionarias/metabolismo , Células Enteroendocrinas/fisiología , Islotes Pancreáticos/crecimiento & desarrollo , Hormonas Pancreáticas/biosíntesis , Hormonas Peptídicas/biosíntesis , Células Cultivadas , Ghrelina , Humanos , Islotes Pancreáticos/citología , Islotes Pancreáticos/metabolismo , Páncreas/citología , Hormonas Pancreáticas/aislamiento & purificaciónRESUMEN
The potential of human embryonic stem (hES) cells to differentiate into cell types of a variety of organs has generated much excitement over the possible use of hES cells in therapeutic applications. Of great interest are organs derived from definitive endoderm, such as the pancreas. We have focused on directing hES cells to the definitive endoderm lineage as this step is a prerequisite for efficient differentiation to mature endoderm derivatives. Differentiation of hES cells in the presence of activin A and low serum produced cultures consisting of up to 80% definitive endoderm cells. This population was further enriched to near homogeneity using the cell-surface receptor CXCR4. The process of definitive endoderm formation in differentiating hES cell cultures includes an apparent epithelial-to-mesenchymal transition and a dynamic gene expression profile that are reminiscent of vertebrate gastrulation. These findings may facilitate the use of hES cells for therapeutic purposes and as in vitro models of development.
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Técnicas de Cultivo de Célula/métodos , Endodermo/citología , Endodermo/fisiología , Células Madre/citología , Células Madre/fisiología , Ingeniería de Tejidos/métodos , Animales , Diferenciación Celular , Proliferación Celular , Células Cultivadas , Humanos , RatonesRESUMEN
We report the first endothelial lineage-specific transgenic mouse allowing live imaging at subcellular resolution. We generated an H2B-EYFP fusion protein which can be used for fluorescent labeling of nucleosomes and used it to specifically label endothelial cells in mice and in differentiating embryonic stem (ES) cells. A fusion cDNA encoding a human histone H2B tagged at its C-terminus with enhanced yellow fluorescent protein (EYFP) was expressed under the control of an Flk1 promoter and intronic enhancer. The Flk1::H2B-EYFP transgenic mice are viable and high levels of chromatin-localized reporter expression are maintained in endothelial cells of developing embryos and in adult animals upon breeding. The onset of fluorescence in differentiating ES cells and in embryos corresponds with the beginning of endothelial cell specification. These transgenic lines permit real-time imaging in normal and pathological vasculogenesis and angiogenesis to track individual cells and mitotic events at a level of detail that is unprecedented in the mouse.