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| Fusion of uniluminal vascular spheroids: A model for assembly of blood vessels.
March 18, 2010 at 6:57 AM
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| | Fusion of uniluminal vascular spheroids: A model for assembly of blood vessels. Dev Dyn. 2010 Mar 16;239(4):spcone Authors: Fleming PA, Argraves WS, Gentile C, Neagu A, Forgacs G, Drake CJ Zebrafish Intrahepatic Biliary System: Confocal projection through the liver of a 5 day post-fertilization zebrafish larva immunostained with antibodies raised against the human multidrug resistance protein-1 (red), also known as Pglcyoprotein, an ABC transporter in the hepatocyte canalicular membrane, and a novel zebrafish epitope 2F11 (green) that recognizes biliary epithelial cells. Hepatocytes secrete bile through their canaliculus into the intrahepatic biliary duct network. 10 mum z-stack. From Lorent et al., Developmental Dynamics 239:398-406, 2010. PMID: 20235182 [PubMed - as supplied by publisher] | | |
| Bio-electrospraying and droplet-based microfluidics: control of cell numbers within living residues.
March 18, 2010 at 6:57 AM
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| | Bio-electrospraying and droplet-based microfluidics: control of cell numbers within living residues. Biomed Mater. 2010 Mar 16;5(2):21001 Authors: Hong J, Demello AJ, Jayasinghe SN Bio-electrospraying (BES) has demonstrated great promise as a rapidly evolving strategy for tissue engineering and regenerative biology/medicine. Since its discovery in 2005, many studies have confirmed that cells (immortalized, primary and stem cells) and whole organisms (Danio rerio, Xenopus tropicalis, Caenorhabditis elegans to Drosophila) remain viable post-bio-electrospraying. Although this bio-protocol has achieved much, it suffers from one crucial problem, namely the ability to precisely control the number of cells within droplets and or encapsulations. If overcome, BES has the potential to become a high-efficiency biotechnique for controlled cell encapsulation, a technique most useful for a wide range of applications in biology and medicine ranging from the forming of three-dimensional cultures to an approach for treating diseases such as type I diabetes. In this communication, we address this issue by demonstrating the coupling of BES with droplet-based m! icrofluidics for controlling live cell numbers within droplets and residues. PMID: 20234087 [PubMed - as supplied by publisher] | | |
| Adipocyte-derived basement membrane extract with biological activity: applications in hepatocyte functional augmentation in vitro.
March 18, 2010 at 6:57 AM
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| | Adipocyte-derived basement membrane extract with biological activity: applications in hepatocyte functional augmentation in vitro. FASEB J. 2010 Mar 16; Authors: Sharma NS, Nagrath D, Yarmush ML Natural and synthetic biomaterials utilized in tissue engineering applications require a dynamic interplay of complex macromolecular compositions of hydrated extracellular matrices (ECMs) and soluble growth factors. The challenges in utilizing synthetic ECMs is the effective control of temporal and spatial complexity of multiple signal presentation, as compared to natural ECMs that possess the inherent properties of biological recognition, including presentation of receptor-binding ligands, susceptibility to cell-triggered proteolytic degradation, and remodeling. We have developed a murine preadipocyte differentiation system for generating a natural basement membrane extract (Adipogel) comprising ECM proteins (collagen IV, laminin, hyaluronan, and fibronectin) and including relevant growth factors (hepatocyte growth factor, vascular endothelial growth factor, and leukemia inhibitory factor). We have shown the effective utilization of the growth factor-enriched ext! racellular matrix for enhanced albumin synthesis rate of primary hepatocyte cultures for a period of 10 d as compared to collagen sandwich cultures and comparable or higher function as compared to Matrigel cultures. We have also demonstrated comparable cytochrome P450 1A1 activity for the collagen-Adipogel condition to the collagen double-gel and Matrigel culture conditions. A metabolic analysis revealed that utilization of Adipogel in primary hepatocyte cultures increased serine, glycine, threonine, alanine, tyrosine, valine, methionine, lysine, isoleucine, leucine, phenylalanine, taurine, cysteine, and glucose uptake rates to enhance hepatocyte protein synthesis as compared to collagen double-gel cultures. The demonstrated synthesis, isolation, characterization, and application of Adipogel provide immense potential for tissue engineering and regenerative medicine applications.-Sharma, N. S., Nagrath, D., Yarmush, M. L. Adipocyte-derived basement membrane extract with biol! ogical activity: applications in hepatocyte functional augment! ation in vitro. PMID: 20233948 [PubMed - as supplied by publisher] | | |
| Thiol-Containing Degradable Poly(thiourethane-urethane)s for Tissue Engineering.
March 18, 2010 at 6:57 AM
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| | Thiol-Containing Degradable Poly(thiourethane-urethane)s for Tissue Engineering. J Biomater Sci Polym Ed. 2010;21(4):477-91 Authors: Eglin D, Griffon S, Alini M Poly(thiourethane-urethane)s with varying amounts of sulphur were synthesised by a two-step polycondensation consisting of the sequential addition of 1,6-hexamethylene diisocyanate and bis(2-mercaptoethyl) ether in a poly(epsilon-caprolactone) diol solution. Polymers prepared had high weight-average molecular weight and typical microdomains separation, as shown by size-exclusion chromatography and thermal analysis. Polymer surfaces were characterized by X-ray photoelectron spectroscopy and atomic force microscopy. The quantification of thiol groups at the surface was assessed using a fluorescent assay. Thiol concentration ranged between 7 and 14 nmol/cm, and was directly related to the amount of sulphur introduced in the polymerization and the macromolecule chains orientation at the surfaces. A preliminary in vitro degradation study and a proliferation assay were performed. The poly(thiourethane-urethane)s may have important applications as biodegradable and bioco! mpatible materials for cartilage and bone tissue engineering. The surface thiol groups add the prospect of further functionalization. This is an important benefit compared to biodegradable poly(urethane)s that usually present low biological activity. PMID: 20233504 [PubMed - in process] | | |
| Adipose tissue formation in collagen scaffolds with different biodegradabilities.
March 18, 2010 at 6:57 AM
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| | Adipose tissue formation in collagen scaffolds with different biodegradabilities. J Biomater Sci Polym Ed. 2010;21(4):463-76 Authors: Kimura Y, Inamoto T, Tabata Y In vivo adipose tissue regeneration by preadipocytes was evaluated by combining them with collagen sponges with different biodegradabilities and gelatin microspheres incorporating basic fibroblast growth factor (bFGF) for the controlled release. The collagen sponge biodegradability was regulated from 1-4 weeks by changing the cross-linking conditions in collagen sponge preparation. The time profile of bFGF release was controlled from 1-5 weeks by the biodegradability of gelatin microspheres used. The collagen sponges combined with human preadipocytes and gelatin microspheres incorporating bFGF were implanted into the back subcutis of nude mice to evaluate the adipose tissue regeneration. The regeneration of adipose tissue was observed in every collagen sponge. The area of regenerated adipose tissue was maximal in the collagen sponge with a degradation time of 2 weeks. No influence of the time profile of bFGF release on the area of regenerated adipose tissue was de! tected. PMID: 20233503 [PubMed - in process] | | |
| Development of thick and highly cell-incorporated engineered tissues by hydrogel template approach with basic fibroblast growth factor or ascorbic Acid.
March 18, 2010 at 6:57 AM
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| | Development of thick and highly cell-incorporated engineered tissues by hydrogel template approach with basic fibroblast growth factor or ascorbic Acid. J Biomater Sci Polym Ed. 2010;21(4):415-28 Authors: Yoshida H, Matsusaki M, Akashi M We have previously reported a hydrogel template approach for the construction of centimeter-sized three-dimensional (3D) engineered tissues composed of cultured cells and extracellular matrices (ECM) produced by the cells. However, the interior of the engineered tissues was low in cell density; thus, it was pouched and non-dense morphologies. In this study, we developed thick and highly cell-incorporated engineered tissues by using basic fibroblast growth factor (bFGF) and ascorbic acid 2-phosphate (Asc 2-P). bFGF was loaded into freeze-dried poly(gamma-glutamic acid) hydrogels with disulfide cross-links (gamma-PGA-SS gels) as a template to enhance cell growth. After prescribed times of cell culture, the scaffolds were decomposed by adding a biocompatible reductant, cysteine, and cell proliferation and collagen production were investigated. The loading of bFGF into the scaffolds enhanced cellular invasion and proliferation. Meanwhile, the addition of Asc 2-P to th! e culture medium induced collagen production from the adhered fibroblasts. However, Asc 2-P did not affect cellular invasion into the template gamma-PGA-SS gels. The volume and weight of the obtained tissues using bFGF after 28 days of culture were 1.3- and 1.4-fold higher than those of control tissues. The thick and highly cell-incorporated 3D-engineered tissues can be useful as a novel cell implantation material for tissue engineering. PMID: 20233500 [PubMed - in process] | | |
| In vivo ultrasound assisted tissue engineered mandibular condyle: A pilot study in rabbits.
March 18, 2010 at 6:57 AM
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| | In vivo ultrasound assisted tissue engineered mandibular condyle: A pilot study in rabbits. Tissue Eng Part C Methods. 2010 Mar 16; Authors: El-Bialy T, Uludag H, Jomha N, Badylak SF Tissue engineering of articular condyles encounters many challenges, especially restoring adequate mechanical strength that is correlated to matrix production by the tissue engineered mandibular condyles (TEMCs). Low Intensity Pulsed Ultrasound (LIPUS) has been shown to enhance cell expansion, differentiation and matrix production by different cells. Objective: This study evaluated effect of daily LIPUS treatment (in-vitro and in a pilot study in-vivo) for four weeks on matrix production and functional integration of the TEMCs in rabbits. Methods: Bone marrow stromal cells (BMSC) were isolated from the femoral bones of skeletally mature New Zealand rabbits, expanded and differentiated into chondrogenic and osteogenic lineages. Animals were divided into four groups as follows: 1) TEMCs and LIPUS treatment; 2) TEMCs without LIPUS treatment; 3) empty scaffold and LIPUS treatment, and 4) empty scaffolds without LIPUS treatment. Results: In-vitro results showed that LI! PUS enhances chondrogenic and osteogenic differentiation of BMSC. The in-vivo study showed that LIPUS led to better structural formation (namely new osteogenic and chondrogenic tissue formation) and integration of the newly formed tissues and original condylar bone of the TEMCs than those without LIPUS treatment. LIPUS effected a small amount of tissue regeneration in the empty scaffolds; while empty scaffolds without LIPUS treatment showed no signs of repair. Conclusions: The preliminary results of this pilot study suggest that LIPUS can enhance tissue engineered mandibular condyles both in-vitro and in-vivo. PMID: 20233011 [PubMed - as supplied by publisher] | | |
| Engineered cartilage heals skull defects.
March 18, 2010 at 6:57 AM
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| | Engineered cartilage heals skull defects. Am J Orthod Dentofacial Orthop. 2010 Feb;137(2):162.e1-9; discussion 162-3 Authors: Doan L, Kelley C, Luong H, English J, Gomez H, Johnson E, Cody D, Duke PJ INTRODUCTION: The purposes of this study were to differentiate embryonic limb bud cells into cartilage, characterize the nodules produced, and determine their ability to heal a mouse skull defect. METHODS: Aggregated mouse limb bud cells (E12-E12.5), cultured in a bioreactor for 3 weeks, were analyzed by histology or implanted in 6 skull defects. Six controls had no implants. The mice were scanned with microcomputed tomography weekly. At 2 and 4 weeks, a mouse from each group was killed, and the defect region was prepared for histology. RESULTS: Chondrocytes in nodules were mainly hypertrophic. About 90% of the nodules mineralized. BrdU staining showed dividing cells in the perichondrium. Microcomputed tomography scans showed increasing minerals in implanted nodules that completely filled the defect by 6 weeks; defects in the control mice were not healed by then. At 2 and 4 weeks, the control skull sections showed only a thin bony layer over the defect. At 2 weeks! , bone and cartilage filled the defects with implants, and the implants were well integrated with the adjacent cortical bone. At 4 weeks, the implant had turned almost entirely into bone. CONCLUSIONS: Cartilage differentiated in the bioreactor and facilitated healing when implanted into a defect. Engineering cartilage to replace bone is an alternative to current methods of bone grafting. PMID: 20152663 [PubMed - indexed for MEDLINE] | | |
| Quantitative structure-cytotoxicity relationship of newly synthesized tropolones determined by a semiempirical molecular-orbital method (PM5).
March 18, 2010 at 6:57 AM
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| | Quantitative structure-cytotoxicity relationship of newly synthesized tropolones determined by a semiempirical molecular-orbital method (PM5). Anticancer Res. 2010 Jan;30(1):129-33 Authors: Ishihara M, Wakabayashi H, Motohashi N, Sakagami H A semiempirical molecular-orbital method (CONFLEX/PM5) was applied to delineate the relationship between the cytotoxicity (evaluated by 50% cytotoxic concentration, CC(50)) of twenty-four tropolone-related compounds and their molecular weight or one of the following eleven chemical descriptors: the heat of formation (COSMO, non-COSMO; kcal/mole), stability of hydration (=COSMO-nonCOSMO (DeltaH); kcal/mole), dipole moment (D), hydrophobicity (log P), highest occupied molecular orbital energy (E(HOMO); eV), lowest unoccupied molecular orbital energy (E(LUMO); eV), absolute hardness [eta=(E(LUMO)-E(HOMO))/2; eV)], absolute electron negativity [chi=-(E(LUMO)+E(HOMO))/2; eV], reactivity index (omega=chi(2)/2eta; eV), surface area (A(2)) and volume (A(3)) of the molecule. No good correlation was found with the unseparated twenty-four compounds all together, but modest to high correlation was found after separation into three different groups of compounds, depending on t! he structural similarity. Particular descriptors could be used to evaluate the biological activity of newly synthesized tropolones. PMID: 20150627 [PubMed - indexed for MEDLINE] | | |
| Recombinant human growth hormone secreted from tissue-engineered bioartificial muscle improves left ventricular function in rat with acute myocardial infarction.
March 18, 2010 at 6:57 AM
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| | Recombinant human growth hormone secreted from tissue-engineered bioartificial muscle improves left ventricular function in rat with acute myocardial infarction. Chin Med J (Engl). 2009 Oct 5;122(19):2352-9 Authors: Rong SL, Wang YJ, Wang XL, Lu YX, Chang C, Wang FZ, Liu QY, Liu XY, Gao YZ, Mi SH BACKGROUND: Experimental studies and preliminary clinical studies have suggested that growth hormone (GH) treatment may improve cardiovascular parameters in chronic heart failure (CHF). Recombinant human GH (rhGH) has been delivered by a recombinant protein, by plasmid DNA, and by genetically engineered cells with different pharmacokinetic and physiological properties. The present study aimed to examine a new method for delivery of rhGH using genetically modified bioartificial muscles (BAMs), and investigate whether the rhGH delivered by this technique improves left ventricular (LV) function in rats with CHF. METHODS: Primary skeletal myoblasts were isolated from several Sprague-Dawley (SD) rats, cultured, purified, and retrovirally transduced to synthesize and secrete human rhGH, and tissue-engineered into implantable BAMs. Ligation of the left coronary artery or sham operation was performed. The rats that underwent ligation were randomly assigned to 2 groups: CH! F control group (n = 6) and CHF treatment group (n = 6). The CHF control group received non-rhGH-secreting BAM (GFP-BAMs) transplantation, and the CHF treatment group received rhGH-secreting BAM (GH-BAMs) transplantation. Another group of rats served as the sham operation group, which was also randomly assigned to 2 subgroups: sham control group (n = 6) and sham treatment group (n = 6). The sham control group underwent GFP-BAM transplantation, and the sham treatment group underwent GH-BAM transplantation. GH-BAMs and GFP-BAMs were implanted subcutaneously into syngeneic rats with ligation of the left coronary artery or sham operation was performed. Eight weeks after the treatment, echocardiography was performed. hGH, insulin-like growth factor-1 (IGF-1) and TNF-alpha levels in rat serum were measured by radioimmunoassay and ELISA, and then the rats were killed and ventricular samples were subjected to immunohistochemistry. RESULTS: Primary rat myoblasts were retrovirally tr! ansduced to secrete rhGH and tissue-engineered into implantabl! e BAMs c ontaining parallel arrays of postmitotic myofibers. In vitro, they secreted 1 to 2 microg of bioactive rhGH per day. When implanted into syngeneic rat, GH-BAMs secreted and delivered rhGH. Eight weeks after therapy, LV ejection fraction (EF) and fractional shortening (FS) were significantly higher in CHF rats treated with GH-BAMs than in those treated with GFP-BAMs ((65.0 +/- 6.5)% vs (48.1 +/- 6.8)%, P < 0.05), ((41.3 +/- 7.4)% vs (26.5 +/- 7.1)%, P < 0.05). LV end-diastolic dimension (LVEDD) was significantly lower in CHF rats treated with GH-BAM than in CHF rats treated with GFP-BAM (P < 0.05). The levels of serum GH and IGF-1 were increased significantly in both CHF and sham rats treated with GH-BAM. The level of serum TNF-alpha decreased more significantly in the CHF treatment group than in the CHF control group. CONCLUSIONS: rhGH significantly improves LV function and prevents cardiac remodeling in rats with CHF. Genetically modified tissue-engineered bioartif! icial muscle provides a method delivering recombinant protein for the treatment of heart failure. PMID: 20079139 [PubMed - indexed for MEDLINE] | | |
| A hierarchical response of cells to perpendicular micro- and nanometric textural cues.
March 18, 2010 at 6:57 AM
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| | A hierarchical response of cells to perpendicular micro- and nanometric textural cues. IEEE Trans Nanobioscience. 2009 Sep;8(3):219-25 Authors: Seunarine K, Curtis AS, Meredith DO, Wilkinson CD, Riehle MO, Gadegaard N In this paper, we report on the influence of shallow micro- and nanopatterned substrata on the attachment and behavior of a human fibroblast [human telomerase transfected immortalized (hTERT)] cells. We identify a hierarchy of textural guidance cues with respect to cell alignment on these substrates. Cells were seeded and cultured for 48 h on silicon substrates patterned with two linear textures overlaid at 90 degrees, both with 24 microm pitch: a micrograting and a nanopattern of rows of 140- nm-diameter pits arranged in a rectangular array with 300 nm centre-to-centre spacing. The cell response to these textures was shown to be highly dependent on textural feature dimensions. We show that cells align to the stripes of nanopits. Stripes of 30-nm deep nanopits were also shown to elicit a stronger response from cells than 160-nm deep nanopits. PMID: 19278933 [PubMed - indexed for MEDLINE] | | | | 
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