Cellartis | Date: 2011-06-20
The present invention relates to a novel hepatocyte-like cell population derived from hBS cells and to the potential use of such heopatocyte-like cells in e.g. medical treatment, drug screening and toxicity testing. Furthermore, the invention relates to 5 hepatoblast-like cells that may have suitable characteristics so that they can be used for the same applications as the hepatocyte-like cells and that furthermore may be used in in vitro studies of hepatogenesis such as early hepatogenesis or hepatoregenerative disorders. Both the hepatocyte-like and the hepatoblast-like cells according to the invention express drug transporter and/or drug metabolising 10 characteristics either at the gene or protein expression level.
Cellartis and Novo Nordisk AS | Date: 2010-05-28
The present invention relates to a method to control differentiation of human pluripotent stem cells, including human balstocyst derived stem (hBS) cells and to obtain specific endoderm cells. In particular, present invention relates to the use of FGF2 as the key factor in a specific concentration to control differentiation of definitive endoderm cells derived from hPS cells to specific endoderm cells. The invention also provides methods of obtaining endoderm cells comprising the use of FGFR and activation of the MAPK signalling pathway.
Jonsson M.K.B.,University Utrecht |
Vos M.A.,University Utrecht |
Mirams G.R.,University of Oxford |
Duker G.,Astrazeneca |
And 3 more authors.
Journal of Molecular and Cellular Cardiology | Year: 2012
Human embryonic stem cell-derived cardiomyocytes (hESC-CM) have been proposed as a new model for safety pharmacology. So far, a thorough description of their basic electrophysiology and extensive testing, and mechanistic explanations, of their overall pro-arrhythmic ability is lacking. Under standardized conditions, we have evaluated the sensitivity of hESC-CM to proarrhythmic provocations by blockade of hERG and other channels. Using voltage patch clamp, some ion current densities (pA/pF) in hESC-CM were comparable to adult CM: I Kr (-12.5±6.9), I Ks (0.65±0.12), I Na,peak (-72±21), I Na,late (-1.10±0.36), and I Ca,L (-4.3±0.6). I f density was larger (-10±1.1) and I K1 not existent or very small (-2.67±0.3). The low I K1 density was corroborated by low KCNJ2 mRNA levels. Effects of pro-arrhythmic compounds on action potential (AP) parameters and provocation of early afterdepolarizations (EADs) revealed that Chromanol293B (100μmol/l) and Bay K8644 (1μmol/l) both significantly prolonged APD 90. ATX-II (<1μmol/l ) and BaCl 2 (10μmol/l ) had no effect on APD. The only compound that triggered EADs was hERG blocker Cisapride. Computer simulations and AP clamp showed that the immature AP of hESC-CM prevents proper functioning of I Na-channels, and result in lower peak/maximal currents of several other channels, compared to the adult situation. Lack of functional I K1 channels and shifted I Na channel activation cause a rather immature electrophysiological phenotype in hESC-CM, and thereby limits the potential of this model to respond accurately to pro-arrhythmic triggers other than hERG block. Maturation of the electrical phenotype is a prerequiste for future implementation of the model in arrhythmogenic safety testing. © 2012 Elsevier Ltd. Source
Sartipy P.,Cellartis |
Stem Cells | Year: 2011
Considering the costs associated with drug development, there are billions of dollars to be saved by reducing latestage attrition in the pharmaceutical industries. Reports on the use of human pluripotent stem cells (hPSCs) and their functional derivatives in applications for safety assessment of drugs have begun to appear in the scientific literature. These reports are encouraging and fuel further developments of improved human cellular models that may increase the clinical relevance and reduce the need of experimental animals in preclinical drug discovery. However, a few factors still limit the general and wide-spread industry implementation of these new stem cell-based models, including cost of manufacture, level of functionality of the differentiated cells, assay validation, verification of human relevance, and benchmarking to conventional models. This review discusses the emerging field of hPSC-based models for drug discovery and development with a focus on cardiac and hepatic toxicity testing and how these approaches may improve current applications used in the pharmaceutical industry. Although much research remains to make hPSC-based models mainstream tools in the industry, importantly, this review highlights currently available opportunities. in addition, a forward looking discussion on novel applications using tissue preparations generated from hPSCs illustrates the opportunities to create complex models in vitro with the aim of simulating the systemic response of a drug in vivo. © AlphaMed Press. Source
Tostoes R.M.,ITQB UNL |
Leite S.B.,ITQB UNL |
Serra M.,ITQB UNL |
Jensen J.,Cellartis |
And 4 more authors.
Hepatology | Year: 2012
Primary cultures of human hepatocyte spheroids are a promising in vitro model for long-term studies of hepatic metabolism and cytotoxicity. The lack of robust methodologies to culture cell spheroids, as well as a poor characterization of human hepatocyte spheroid architecture and liver-specific functionality, have hampered a widespread adoption of this three-dimensional culture format. In this work, an automated perfusion bioreactor was used to obtain and maintain human hepatocyte spheroids. These spheroids were cultured for 3-4 weeks in serum-free conditions, sustaining their phase I enzyme expression and permitting repeated induction during long culture times; rate of albumin and urea synthesis, as well as phase I and II drug-metabolizing enzyme gene expression and activity of spheroid hepatocyte cultures, presented reproducible profiles, despite basal interdonor variability (n = 3 donors). Immunofluorescence microscopy of human hepatocyte spheroids after 3-4 weeks of long-term culture confirmed the presence of the liver-specific markers, hepatocyte nuclear factor 4α, albumin, cytokeratin 18, and cytochrome P450 3A. Moreover, immunostaining of the atypical protein kinase C apical marker, as well as the excretion of a fluorescent dye, evidenced that these spheroids spontaneously assemble a functional bile canaliculi network, extending from the surface to the interior of the spheroids, after 3-4 weeks of culture. Conclusion: Perfusion bioreactor cultures of primary human hepatocyte spheroids maintain a liver-specific activity and architecture and are thus suitable for drug testing in a long-term, repeated-dose format. © 2011 American Association for the Study of Liver Diseases. Source