Other articles by Maria Rende on PubMed

• Biotransformation and Liver-specific Functions of Human Hepatocytes in Culture on RGD-immobilized Plasma-processed Membranes Biomaterials. Jul, 2005  |   Pubmed ID: 15701372 In this paper we report on the metabolic response of human hepatocytes grown on polyethersulfone membranes surface modified with a plasma-deposited acrylic acid coating and RGD peptide covalently immobilized through a "spacer arm" molecule. The modified surfaces were characterized by means of X-ray photoelectron spectroscopy and water contact angle measurements. The performance of modified and unmodified membranes was evaluated by assessing the expression of liver specific and biotransformation functions of human hepatocytes. Diclofenac, a non-steroidal anti-inflammatory drug, was used to investigate the biotransformation functions. Surface-modified membranes elicit specific cellular responses and induce hepatocytes to enhance the synthesis rate of albumin and urea, particularly in the presence of diclofenac. Also the biotransformation functions were expressed at high levels.
• Effect of Isoliquiritigenin on Viability and Differentiated Functions of Human Hepatocytes Maintained on PEEK-WC-polyurethane Membranes Biomaterials. Nov, 2005  |   Pubmed ID: 15927248 In this study, we tested the ability of microporous membranes synthesised from a polymeric blend of modified polyetheretherketone (PEEK-WC) and polyurethane (PU) to support long-term maintenance and differentiation of human liver cells. The effect of isoliquiritigenin (ISL), which is a component of liquorice extract, exhibiting growth stimulatory and antiproliferative dose-dependent effect was investigated by comparing cultures treated with ISL with those untreated. To this purpose, flat-sheet membranes were prepared by a blend of PEEK-WC and PU polymers by phase inverse technique. The morphological and physico-chemical properties were characterised, respectively, by scanning electron microscopy and water contact angle measurements. Human hepatocytes cultured on PEEK-WC-PU membranes were constant up to 1 month albumin production and urea synthesis as well as the synthesis of total proteins. The liver-specific functions were expressed at high levels when cells were cultured on membranes with respect to collagen. Also the biotransformation functions were maintained for all culture periods: the ISL elimination rate increased during the culture time and high values were measured up to 22 days. Thereafter, a decrease was observed. ISL stimulated the proliferation of hepatocytes cultured on both substrata but did not affect their liver-specific functions. Hepatocytes cultured on PEEK-WC-PU membranes responded very well to ISL and expressed high levels of P450 cytochrome. These results demonstrated that long-term maintenance of human liver differentiation can be achieved on PEEK-WC-PU membranes. The incubation with ISL at the investigated concentration could stimulate the proliferation of human hepatocytes in biohybrid systems.
• Long-term Maintenance of Human Hepatocytes in Oxygen-permeable Membrane Bioreactor Biomaterials. Sep, 2006  |   Pubmed ID: 16753210 An oxygen-permeable membrane bioreactor utilizing human hepatocytes has been tested in this study. In the bioreactor, human hepatocytes were cultured between flat-sheet gas-permeable polymeric membranes, which ensure the diffusion of O(2) and CO(2) providing a support for cell anchorage and growth and permit the online observation of the cells with an inverse microscope. This bioreactor allows a direct oxygenation of cells adhered on membranes and of the medium overlaying cells simulating in vivo sinusoidal organization. Human hepatocytes were cultured in the presence of some therapeutic molecules to assess the temporal liver-specific functions of the cells. Interleukin 6 (IL-6), which is a multifactorial proinflammatory cytokine involved in a variety of host defences and pathological processes, and diclofenac, an arylacetic non-steroidal anti-inflammatory drug, were used as therapeutic molecules. The aim of this study was to evaluate the in vitro performance of the small oxygen-permeable membrane bioreactor in the long-term maintenance and differentiation of human hepatocytes under in-vivo-like conditions. The fluid dynamics of the bioreactor were characterized before using it for human cell culture. The functional response to a step challenge in the medium of IL-6 (120 pg/ml), diclofenac (80 microm) and IL-6 and diclofenac together was investigated. The ability of hepatocytes to perform liver-specific functions in terms of urea and albumin synthesis, as well as secretion of total proteins, was maintained for 32 days. Also, the diclofenac biotransformation functions were sustained as the formation of the metabolites 4'-OH-diclofenac and 5-OH-diclofenac lactam demonstrated. This study attested the feasibility of the membrane bioreactor as an in vitro simple model system that allows human hepatocytes to be maintained in a differentiated state similar to that in vivo.
• Galactose Derivative Immobilized Glow Discharge Processed Polyethersulfone Membranes Maintain the Liver Cell Metabolic Activity Journal of Nanoscience and Nanotechnology. Aug, 2006  |   Pubmed ID: 17037840 New strategies aimed to surface modification of polymeric membranes are crucial to optimise cell-biomaterial interactions in vivo and in vitro biohybrid systems. In this paper, we investigated the surface modification of Polyethersulfone (PES) membranes by plasma polymerisation of acrylic acid monomers (PES-pdAA) and by immobilization of galactonic acid through a hydrophilic "spacer arm" molecule (PES-pdAA-SA-GAL). The modification steps were characterised by high resolution X-ray photoelectron spectroscopy. The performance of modified and unmodified membranes was evaluated by assessing the expression of liver specific biotransformation functions of pig and human hepatocytes. Human liver cells cultured on PES-pdAA-SA-GAL membranes displayed an enhanced albumin production, urea synthesis and protein secretion for 24 days of culture. The immobilisation of galactose derivative units on the membrane allowed specific interactions with hepatocytes biomimicking the cellular microenvironment and produced an improvement of the long-term maintenance and differentiation of human hepatocytes.
• Human Hepatocyte Morphology and Functions in a Multibore Fiber Bioreactor Macromolecular Bioscience. May, 2007  |   Pubmed ID: 17457942 The viability and liver specific functions of human hepatocytes in a multibore fiber bioreactor are reported. Human hepatocytes were cultured in the intraluminal compartment of the bioreactor. Human hepatocytes on the membranes maintained their round shape and showed focal adhesions as sites of interaction with the membrane surface. Cells in the bioreactor expressed liver specific functions, including synthetic and detoxification activity up to 14 d of culture. The results demonstrate that human hepatocytes cultured in the multibore fiber bioreactor are able to sustain the same in vivo liver functions in vitro.
• Human Lymphocyte PEEK-WC Hollow Fiber Membrane Bioreactor Journal of Biotechnology. Oct, 2007  |   Pubmed ID: 17905461 In this study we developed a PEEK-WC hollow fiber (HF) membrane bioreactor for the maintenance of human peripheral lymphocytes as model system for the in vitro investigation of disease pathogenesis, chemical effects and individual drug sensitivity. Peripheral lymphocytes isolated from donor's human buffy coat were cultured in the shell compartment of the PEEK-WC-HF bioreactor and stimulated with PHA 5microg/mL for the first 48h of culture to enhance cytokine production and cell proliferation. Thereafter, cells were cultured in the presence of Hypericum perforatum (St. John's wort) in order to induce cytochrome P450s enzymes, CYP2E, involved in the biotransformation of endogenous molecules and exogenous compounds. The metabolic activity of cells with respect to glucose consumption and oxygen uptake was maintained for all the culture time without the addition of mitogen. Two cytokines IL-2 and IL-10, which are specific pattern of lymphocytes T helper 1 and T helper 2, respectively, were produced in the bioreactor up to 14 days of culture. Lymphocytes were also able to biotransform acetaminophen through the formation of the main metabolite paracetamidofenil-beta-glucuronide, which is the product of glucuronidation reaction, as a result of the Hypericum perforatum administration that induced the catalytic activity of the CYP2E1. These results demonstrated the usefulness of the bioreactor as the support system that reproduces physiological parameters such as a constant perfusion of medium, nutrients and oxygen maintaining the in vitro integrity of lymphocyte viability and functions.
• Human Hepatocyte Functions in a Crossed Hollow Fiber Membrane Bioreactor Biomaterials. May, 2009  |   Pubmed ID: 19185912 An important challenge in liver tissue engineering is the development of bioartificial systems that are able to favour the liver reconstruction and to modulate liver cell behaviour. A crossed hollow fiber membrane bioreactor was developed to support the long-term maintenance and differentiation of human hepatocytes. The bioreactor consists of two types of hollow fiber (HF) membranes with different molecular weight cut-off (MWCO) and physico-chemical properties cross-assembled in alternating manner: modified polyetheretherketone (PEEK-WC) and polyethersulfone (PES), used for the medium inflow and outflow, respectively. The combination of these two fiber set produces an extracapillary network for the adhesion of cells and a high mass exchange through the cross-flow of culture medium. The transport of liver specific products such as albumin and urea together with the transport of drug such as diazepam was modelled and compared with the experimental metabolic data. The theoretical metabolite concentration differed 7.5% for albumin and 5% for urea with respect to experimental data. The optimised perfusion conditions of the bioreactor allowed the maintenance of liver functions in terms of urea synthesis, albumin secretion and diazepam biotransformation up to 18 days of culture. In particular the good performance of the bioreactor was confirmed by the high rate of urea synthesis (28.7 microg/h 10(6) cells) and diazepam biotransformation. In the bioreactor human hepatocytes expressed at high levels the individual cytochrome P450 isoenzymes involved in the diazepam metabolism. The results demonstrated that crossed HF membrane bioreactor is able to support the maintenance of primary human hepatocytes preserving their liver specific functions for all investigated period. This device may be a potential tool in the liver tissue engineering for drug metabolism/toxicity testing and study of disease pathogenesis alternatively to animal experimentation.
• Distinct Alpha Subunits of the GABAA Receptor Are Responsible for Early Hippocampal Silent Neuron-related Activities Hippocampus. Nov, 2009  |   Pubmed ID: 19338020 The modulatory actions of GABA(A) receptor subunits are crucial for morphological and transcriptional neuronal activities. In this study, growth of hamster hippocampal neurons on biohybrid membrane substrates allowed us to show for the first time that the two major GABA(A) alpha receptor subunits (alpha(2,5)) are capable of early neuronal shaping plus expression differences of some of the main neuronal cytoskeletal factors (GAP-43, the neurotrophin--BDNF) and of Gluergic subtypes. In a first case the inverse alpha(5) agonist (RY-080) seemed to account for the reduction of dendritic length at DIV7, very likely via lower BDNF levels. Conversely, the effects of the preferentially specific agonist for hippocampal alpha(2) subunit (flunitrazepam) were, instead, directed at the formation of growth cones at DIV3 in the presence of greatly (P < 0.01) diminished GAP-43 levels as displayed by strongly reduced axonal sprouting. It is interesting to note that concomitantly to these morphological variations, the transcription of some Gluergic receptor subtypes resulted to be altered. In particular, flunitrazepam was responsible for a distinctly rising expression of axonal NR1 mRNA levels from DIV3 (P < 0.01) until DIV7 (P < 0.001), whereas RY-080 evoked a very great (P < 0.001) downregulation of dendritic GluR2 at only DIV7. Together, our results demonstrate that GABA(A) alpha(2,5) receptor-containing subunits by regulating the precise synchronization of cytoskeletal factors are considered key modulating neuronal elements of hippocampal morphological growth features. Moreover, the notable NR1 and GluR2 transcription differences promoted by these GABA(A) alpha subunits tend to favorably corroborate the early role of alpha(2) + alpha(5) on hippocampal neuronal networks in hibernating rodents through the recruitment and activation of silent neurons, and this may provide useful insights regarding molecular neurodegenerative events.
• Flat and Tubular Membrane Systems for the Reconstruction of Hippocampal Neuronal Network Journal of Tissue Engineering and Regenerative Medicine. Apr, 2012  |   Pubmed ID: 21706777 The selection of appropriate biomaterials that promote cellular adhesion and growth is particularly important for the in vitro reconstruction of neuronal network. This study focused on the development of new polymeric membranes in flat and tubular (hollow-fibre) configurations as novel biomaterials for neuronal outgrowth. Two membrane systems constituted by modified polyetheretherketone (PEEK-WC) and polyacrylonitrile (PAN) membranes were developed and used for the culture of hamster hippocampal neurons. We demonstrated that all investigated membranes supported the adhesion and growth of hippocampal neurons enhancing neuronal differentiation and neurite alignment. The differences in cell behaviours between cells cultured on flat and hollow-fibre (HF) membranes were highlighted by the quantitative analysis of neuronal marker fluorescence intensity, morphometric analysis, RT-PCR analysis and also by metabolic activity measurements. In particular, the PAN HF membranes showed ideal growth culture conditions, guaranteeing adequate levels of metabolic features. Primary hippocampal cells cultured on PAN HF membranes were able to recreate in vitro a 3D neural tissue-like structure that, mimicking the hippocampal tissue, could be used as a tool for the study of natural and pathological neurobiological events. Copyright © 2011 John Wiley & Sons, Ltd.