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Alzenau in Unterfranken, Germany

Glage S.,Hannover Medical School | Lewis A.L.,Biocompatibles UK Ltd | Mertens P.,International Neuroscience Institute | Baltes S.,International Neuroscience Institute | And 2 more authors.
Clinical and Translational Oncology | Year: 2012

Introduction Chemotherapeutic drug-eluting beads (DEBs) are microspheres that are in clinical use for intraarterial chemoembolisation of liver cancer. Here we report on the biocompatibility and anti-tumour effi cacy of DEBs after intratumoral application in a rat BT4Ca glioma model. Methods and results Doxorubicin and irinotecan-eluting DEBs were suspended in a Ca 2+-free aqueous alginate solution that provides a sol-gel transition when injected into the Ca 2+ rich brain tissue. In this way the DEBs are immobilised at the implantation site. Forced elution studies in vitro using a USP-4 fl ow-through apparatus demonstrated that the alginate excipient helped to reduce the burst effect and rate the elution from the beads. From the in vivo evaluation, doxorubicin DEBs demonstrated a signifi cant local toxicity, while irinotecan-loaded DEBs showed good local tissue compatibility. Doxorubicin at higher concentrations and irinotecan-loaded DEBs were found to decrease tumour volume, increase survival time and decrease the Ki67 proliferation index of the tumour. Doxorubicin was shown by fl uorescent microscopy to diffuse into the peritumoral tissue, but also penetrates along white matter tracts, to more distant areas. Discussion We conclude that the alginate suspension of irinotecan DEBs can be considered safe and effective in a clinical setting.

Wright E.J.,University of Manchester | Farrell K.A.,University of Manchester | Malik N.,University of Manchester | Kassem M.,University of Southern Denmark | And 3 more authors.
Stem Cells Translational Medicine | Year: 2012

Stem cell therapy is an exciting and emerging treatment option to promote post-myocardial infarction (post-MI) healing; however, cell retention and efficacy in the heart remain problematic. Glucagon- like peptide-1 (GLP-1) is an incretin hormone with cardioprotective properties but a short halflife in vivo. The effects of prolonged GLP-1 delivery from stromal cells post-MI were evaluated in a porcine model. Human mesenchymal stem cells immortalized and engineered to produce a GLP-1 fusion protein were encapsulated in alginate (bead-GLP-1 MSC) and delivered to coronary artery branches. Control groups were cell-free beads and beads containing unmodified MSCs (bead-MSC), n = 4-5 per group. Echocardiography confirmed left ventricular (LV) dysfunction at time of delivery in all groups. Four weeks after intervention, only the bead-GLP-1 MSC group demonstrated LV function improvement toward baseline and showed decreased infarction area compared with controls. Histological analysis showed reduced inflammation and a trend toward reduced apoptosis in the infarct zone. Increased collagen but fewer myofibroblasts were observed in infarcts of the bead-GLP-1 MSC and bead-MSC groups, and significantly more vessels per mm2 were noted in the infarct of the bead-GLP-1 MSC group. No differences were observed in myocyte cross-sectional area between groups. Post-MI delivery of GLP-1 encapsulated genetically modified MSCs provided a prolonged supply of GLP-1 and paracrine stem cell factors, which improved LV function and reduced epicardial infarct size. This was associated with increased angiogenesis and an altered remodeling response. Combined benefits of paracrine stem cell factors and GLP-1 were superior to those of stem cells alone. These results suggest that encapsulated genetically modified MSCs would be beneficial for recovery following MI. © AlphaMed Press.

Zhang R.,Capital Medical University | Zhang H.,Capital Medical University | Xu L.,Capital Medical University | Ma K.,Capital Medical University | And 4 more authors.
Retina | Year: 2011

Background: To examine the efficacy and safety of an intravitreal cell-based production of glucagon-like peptide-1 (GLP-1) by intravitreally implanted and encapsulated cells. Methods: The experimental study included 12 Sprague-Dawley rats. Four cell beads with a diameter of 600 μm were intravitreally implanted. Each bead contained 3,000 GLP-1-secreting cells, which were encapsulated by a barium cross-linked sodium alginate matrix. At baseline and at each of the follow-up examinations at Day 3, Day 7, and Day 14, 4, 3, 3, and 2 animals, respectively, were killed. The concentration of active GLP-1 in the vitreous body samples was determined by enzyme-linked immunosorbent assay. The retinas were histologically examined. Results: The active GLP-1 concentration in the vitreous samples increased significantly after baseline (<5 pM) to a peak at Day 3 (287 ± 196 pM) and at Day 7 (238 ± 55 pM), before it decreased at Day 14 (70 ± 8 pM). The histologic examinations did not show signs of apoptosis or tissue destruction. Conclusion: The intravitreal application of beads containing alginate-encapsulated cells producing GLP-1 resulted in an intraocular production of GLP-1 with a significant increase in the intraocular GLP-1 concentration, without observed cytotoxic effects. An intravitreal cell-based drug therapy with GLP-1 appears feasible. © The Ophthalmic Communications Society, Inc.

Grein T.A.,Justus Liebig University | Freimark D.,Justus Liebig University | Weber C.,Justus Liebig University | Hudel K.,Martin Christ Gefriertrocknungsanlagen GmbH | And 3 more authors.
International Journal of Artificial Organs | Year: 2010

Human mesenchymal stem cells (hMSCs) have some favorable characteristics like high plasticity, multilineage differentiation potential, and comparably easy handling in vitro, making them of interest for many clinical and therapeutic approaches including cell therapy. For routine applications, these cells have to be stored over a certain period of time without loss of cell vitality and function. An easy way to preserve cells is to store them at temperatures between -80°C and -196°C (liquid nitrogen). To prevent cells from the damage caused by the cryopreservation process and to achieve high cell recovery and vitality, cryoprotectants are used. Typically dimethylsulfoxide, often in combination with serum, is used as a cryoprotectant. However, for clinical approaches, the use of dimethylsulfoxide and serum in patients is problematic for several reasons. Therefore, the cryopreservation of human mesenchymal stem cells for cell therapeutic applications without dimethylsulfoxide and serum demands investigation. In this work, non-toxic alternatives to dimethylsulfoxide such as glycerol or the compatible solutes, proline and ectoin, were analyzed in a serum-free cryomedium with respect to their cryo-protective properties. Different concentrations of the cryoprotectants (1-10% (w/v) ectoin or proline, respectively, or 5-20% (v/v) glycerol) and certain incubation times (0-60 minutes) were investigated with regard to post-thaw cell vitality and cell growth. Our results showed that, in general, cryopreservation with ectoin led to high post-thaw cell survival of up to 72% whereas after cryopreservation with glycerol and proline, the hMSC cells were completely dead (glycerol) or had only poor cell survival (proline, 22%). Moreover, the morphology of the hMSC cells changed to a large and flat phenotype after cryopreservation with proline. These results indicate that glycerol and proline are not suitable for cryopreservation of hMSC. In contrast, ectoin has the potential to replace dimethylsulfoxide as a cryoprotectant in a serum-free cryomedium. © 2010 Wichtig Editore.

Elseberg C.L.,Mittelhessen University of Applied Sciences | Leber J.,Mittelhessen University of Applied Sciences | Salzig D.,Mittelhessen University of Applied Sciences | Wallrapp C.,CellMed AG | And 5 more authors.
International Journal of Artificial Organs | Year: 2012

For cell therapy, a high biomass of human mesenchymal stem cells (hMSCs) is required for clinical applications, such as in the form of encapsulated implants. An easy and reproducible microcarrierbased stirred tank reactor cultivation process for hMSCs in 1.68 L scale is described. To avoid medium changes, studies comparing high-glucose DMEM (DMEM-HG) with low-glucose EMEM were performed showing that high-glucose medium has positive effects on cell proliferation and that cell differentiability remains. Studies on the inoculation strategy and cell density, carrier concentration, volume, and stirrer speed were performed and resulted in a set of optimized parameters, inoculation strategy was found to be 45 minutes of static state and 2 minutes of stirring repeated in 4 cycles. The inoculation density was chosen to be 7×10 3 cells/cm 2, and the carrier concentration of glass surface carrier was 25 g/L. For the described reactor system, a stirrer speed of 120 rpm for the inoculation process and a daily increase of 10 rpm up to 160 rpm were found to be suitable. Process reproducibility was shown by 3 repeated cultivations at the determined set of parameters allowing high biomass values of up to 7×10 8 cells per batch. With DMEM-HG, no limitation of glucose was found, and lactate and ammonia remained lower than critical inhibitory concentrations. Comparison of the static (T-flask) and dynamic cultures in the stirred tank reactor showed for both cases, that cells were of high vitality and both maintained differentiability. In both cases, encapsulation of the cells resulted in high bead vitality, a basic requirement for cell therapy application. © 2012 Wichtig Editore.

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