An efficient, economical slow-freezing method for large-scale human embryonic stem cell banking

Human embryonic stem cells (hESCs) are one of the most interesting cell types for tissue engineering, cell therapy, basic scientific research, and drug screening. Fast advancement in these areas requires the availability of large amounts of safe and well-characterized hESCs from hESC banks. Therefore, optimized freezing protocols, allowing the cryopreservation of large amounts of hESC without direct contact with liquid nitrogen, need to be established. In this study, 6 different cryoprotector combinations [dimethylsulfoxide (DMSO), ethylene glycol, and hydroxyethylstarch (HES)] combined with 2 different application methods were screened with the VUB01 cell line, to establish a new slow-freezing protocol with high recovery rates and a good expansion capacity. Our best conditions were confirmed in 4 other hESC lines: H1, H9, 181, and UGent2. To our knowledge, this is the first time that HES is evaluated as a cryoprotector for hESCs. The use of 5% DMSO + 5% HES combined with a new detachment protocol leads to efficient hESC cryopreservation. This protocol involves treating the hESC colonies with cell dissociation solution, a mild dissociation solution uncommonly used for hESC culture. A recovery ratio ranging from 45.5% to 168.2% was obtained, and these were significantly different from the other tested conditions (Student's t-test, P < 0.05). The cryopreserved hESCs were morphologically comparable to control cells, exhibited a good expansion profile, were positive for pluripotent expression markers, and could still differentiate into the 3 germ layers. This new protocol allows efficient and economical hESC cryopreservation, ideal for hESC banking

The role of scaffold architecture and composition on the bone formation by adipose-derived stem cells

Scaffold architecture and composition are crucial parameters determining the initial cell spatial distribution and consequently bone tissue formation. Three-dimensional poly-ε-caprolactone (PCL) scaffolds with a 0/90° lay-down pattern were plotted and subjected to 1) an oxygen plasma (PCL O) or 2) a post-argon plasma modification with gelatine and fibronectin (PCL Fn). These scaffolds with an open pore structure were compared with more compact scaffolds fabricated by conventional processing techniques: oxidized polylactic acid (LA O) and collagen (COL) scaffolds. Human adipose tissue derived stem cell/scaffold interaction was studied. The study revealed that the biomimetic surface modification of plotted scaffolds did not increase the seeding efficiency. The proliferation and colonization was superior for PCL Fn in comparison with PCL O. The plotted PCL Fn was completely colonized throughout the scaffold whereas conventional scaffolds only at the edge. Protein-based scaffolds (PCL Fn and COL) enhanced the differentiation, although plotted scaffolds showed a delay in their differentiation compared with compact scaffolds. In conclusion, protein modification of plotted PCL scaffolds enhances uniform tissue formation but shows a delayed differentiation in comparison with compact scaffolds. The present study demonstrates that biomimetic PCL scaffolds could serve as a guiding template to obtain a uniform bone tissue formation in vivo

Investigating the stability of plasma polymerized acrylic acid coatings

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Morphometric analyses of the visual pathways in macular degeneration

Introduction. Macular degeneration (MD) causes central visual field loss. When field defects occur in both eyes and overlap, parts of the visual pathways are no longer stimulated. Previous reports have shown that this affects the grey matter of the primary visual cortex, but possible effects on the preceding visual pathway structures have not been fully established. Method. In this multicentre study, we used high-resolution anatomical magnetic resonance imaging and voxel-based morphometry to investigate the visual pathway structures up to the primary visual cortex of patients with age-related macular degeneration (AMD) and juvenile macular degeneration (JMD). Results. Compared to age-matched healthy controls, in patients with JMD we found volumetric reductions in the optic nerves, the chiasm, the lateral geniculate bodies, the optic radiations and the visual cortex. In patients with AMD we found volumetric reductions in the lateral geniculate bodies, the optic radiations and the visual cortex. An unexpected finding was that AMD, but not JMD, was associated with a reduction in frontal white matter volume. Conclusion. MD is associated with degeneration of structures along the visual pathways. A reduction in frontal white matter volume only present in the AMD patients may constitute a neural correlate of previously reported association between AMD and mild cognitive impairment. Keywords: macular degeneration - visual pathway - visual field - voxel-based morphometryComment: appears in Cortex (2013

ATP Augments von Willebrand Factor-dependent Shear-induced Platelet Aggregation through Ca2+-Calmodulin and Myosin Light Chain Kinase Activation

peer reviewedShear stress triggers von Willebrand factor (VWF) binding to platelet glycoprotein Ibalpha and subsequent integrin alpha(IIb)beta(3)-dependent platelet aggregation. Concomitantly, nucleotides are released from plateletdense granules, and ADP is known to contribute to shear-induced platelet aggregation (SIPA). This study shows that ATP also contributes to SIPA. The ATP-gated P2X(1) ion channel induces MLC-mediated cytoskeletal rearrangements that increases platelet degranulation during VWF-triggered platelet activation

Random and aligned plasma-activated nanofibers of different diameters : impact on cell morphology and proliferation

INTRODUCTION: Poly-ε-caprolactone (PCL) is an interesting polymer for tissue engineering purposes due to its good mechanical properties and tunable degradation rate. However, its hydrophobicity raises a big challenge for cell adhesion and proliferation. To overcome this problem, plasma surface treatment could be used. Moreover, surface topography is also described to play an important role in cellular interaction. Therefore, in this study, PCL nanofibers of different diameters and orientations were produced and cellular interaction was evaluated for both untreated and plasma-activated nanofibers. MATERIALS AND METHODS: Random and aligned PCL nanofibers of three different diameters were produced by electrospinning and subsequently plasma-activated. Furthermore, cellular interaction was evaluated by seeding adipose-derived stem cells onto the nanofibers. Cell morphology was evaluated by means of scanning electron microscopy, while cell survival and proliferation was evaluated with live/dead staining and MTT assays. RESULTS AND DISCUSSION: Fiber orientation had a clear influence on cell morphology, with irregular-shaped cells on the random nanofibers and more elongated cells on the aligned nanofibers. Cell proliferation, on the other hand, was similar for random and aligned nanofibers. Due to the incorporation of functional groups, plasma treatment of the PCL nanofibers resulted in higher proliferation rates as compared to untreated samples, both for random and aligned nanofibers. In case of the untreated samples, higher nanofiber diameters seemed to have a positive influence on cell proliferation. For the plasma-treated samples, however, this could not be observed. CONCLUSIONS: To improve cellular interaction with PCL nanofibers, either plasma-treatment or an increase of surface roughness can be employed, but a combination of both has no synergistic effect