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| Designed biomaterials to mimic the mechanical properties of muscles.
May 7, 2010 at 7:59 AM
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| | Designed biomaterials to mimic the mechanical properties of muscles. Nature. 2010 May 6;465(7294):69-73 Authors: Lv S, Dudek DM, Cao Y, Balamurali MM, Gosline J, Li H The passive elasticity of muscle is largely governed by the I-band part of the giant muscle protein titin, a complex molecular spring composed of a series of individually folded immunoglobulin-like domains as well as largely unstructured unique sequences. These mechanical elements have distinct mechanical properties, and when combined, they provide the desired passive elastic properties of muscle, which are a unique combination of strength, extensibility and resilience. Single-molecule atomic force microscopy (AFM) studies demonstrated that the macroscopic behaviour of titin in intact myofibrils can be reconstituted by combining the mechanical properties of these mechanical elements measured at the single-molecule level. Here we report artificial elastomeric proteins that mimic the molecular architecture of titin through the combination of well-characterized protein domains GB1 and resilin. We show that these artificial elastomeric proteins can be photochemically ! crosslinked and cast into solid biomaterials. These biomaterials behave as rubber-like materials showing high resilience at low strain and as shock-absorber-like materials at high strain by effectively dissipating energy. These properties are comparable to the passive elastic properties of muscles within the physiological range of sarcomere length and so these materials represent a new muscle-mimetic biomaterial. The mechanical properties of these biomaterials can be fine-tuned by adjusting the composition of the elastomeric proteins, providing the opportunity to develop biomaterials that are mimetic of different types of muscles. We anticipate that these biomaterials will find applications in tissue engineering as scaffold and matrix for artificial muscles. PMID: 20445626 [PubMed - in process] | | |
| p63 in Skin Development and Ectodermal Dysplasias.
May 7, 2010 at 7:59 AM
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| | p63 in Skin Development and Ectodermal Dysplasias. J Invest Dermatol. 2010 May 6; Authors: Koster MI The transcription factor p63 is critically important for skin development and maintenance. Processes that require p63 include epidermal lineage commitment, epidermal differentiation, cell adhesion, and basement membrane formation. Not surprisingly, alterations in the p63 pathway underlie a subset of ectodermal dysplasias, developmental syndromes in which the skin and skin appendages do not develop normally. This review summarizes the current understanding of the role of p63 in normal development and ectodermal dysplasias.Journal of Investigative Dermatology advance online publication, 6 May 2010; doi:10.1038/jid.2010.119. PMID: 20445549 [PubMed - as supplied by publisher] | | |
| Mesenchymal stem cell therapy for cutaneous radiation syndrome.
May 7, 2010 at 7:59 AM
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| | Mesenchymal stem cell therapy for cutaneous radiation syndrome. Health Phys. 2010 Jun;98(6):858-62 Authors: Akita S, Akino K, Hirano A, Ohtsuru A, Yamashita S Systemic and local radiation injuries caused by nuclear power reactor accidents, therapeutic irradiation, or nuclear terrorism should be prevented or properly treated in order to improve wound management and save lives. Currently, regenerative surgical modalities should be attempted with temporal artificial dermis impregnated and sprayed with a local angiogenic factor such as basic fibroblast growth factor, and secondary reconstruction can be a candidate for demarcation and saving the donor morbidity. Human mesenchymal stem cells and adipose-derived stem cells, together with angiogenic and mitogenic factor of basic fibroblast growth factor and an artificial dermis, were applied over the excised irradiated skin defect and were tested for differentiation and local stimulation effects in the radiation-exposed wounds. The perforator flap and artificial dermal template with growth factor were successful for reconstruction in patients who were suffering from complex und! erlying disease. Patients were uneventfully treated with minimal morbidities. In the experiments, the hMSCs are strongly proliferative even after 20 Gy irradiation in vitro. In vivo, 4 Gy rat whole body irradiation demonstrated that sustained marrow stromal (mesenchymal stem) cells survived in the bone marrow. Immediate artificial dermis application impregnated with cells and the cytokine over the 20 Gy irradiated skin and soft tissues demonstrated the significantly improved fat angiogenesis, architected dermal reconstitution, and less inflammatory epidermal recovery. Detailed understanding of underlying diseases and rational reconstructive procedures brings about good outcomes for difficult irradiated wound healing. Adipose-derived stem cells are also implicated in the limited local injuries for short cell harvesting and processing time in the same subject. PMID: 20445394 [PubMed - in process] | | |
| New emerging concepts in the medical management of local radiation injury.
May 7, 2010 at 7:59 AM
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| | New emerging concepts in the medical management of local radiation injury. Health Phys. 2010 Jun;98(6):851-7 Authors: Benderitter M, Gourmelon P, Bey E, Chapel A, Clairand I, Prat M, Lataillade JJ Treatment of severe radiation burns remains a difficult medical challenge. The response of the skin to ionizing radiation results in a range of clinical manifestations. The most severe manifestations are highly invalidating. Although several therapeutic strategies (excision, skin grafting, skin or muscle flaps) have been used with some success, none have proven entirely satisfying. The concept that stem cell injections could be used for reducing normal tissue injury has been discussed for a number of years. Mesenchymal stem cells therapy may be a promising therapeutic approach for improving radiation-induced skin and muscle damages. Pre-clinical and clinical benefit of mesenchymal stem cell injection for ulcerated skin and muscle restoration after high dose radiation exposure has been successfully demonstrated. Three first patients suffering from severe radiological syndrome were successfully treated in France based on autologous human grade mesenchymal stem cell ! injection combined to plastic surgery or skin graft. Stem cell therapy has to be improved to the point that hospitals can put safe, efficient, and reliable clinical protocols into practice. PMID: 20445393 [PubMed - in process] | | |
| Structural analysis and biomedical applications of dextran produced by a new isolate Pediococcus pentosaceus screened from biodiversity hot spot Assam.
May 7, 2010 at 7:59 AM
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| | Structural analysis and biomedical applications of dextran produced by a new isolate Pediococcus pentosaceus screened from biodiversity hot spot Assam. Bioresour Technol. 2010 May 3; Authors: Patel S, Kasoju N, Bora U, Goyal A Dextran produced by a natural isolate of Pediococcus pentosaceus, screened from Assam, in the Northeastern region of India, was estimated, purified, structure characterised and functionality analysed. The dextran concentration in the cell free supernatant of the isolate P. pentosaceus was 10.2mg/ml. FT-IR analysis revealed the hydroxyl and carboxyl functional groups present in the dextran. (1)H NMR and (13)C NMR spectral data revealed that the dextran has a linear backbone of alpha-(1-->6) linked d-glucose residues. The decrease in viscosity of dextran solution with the increase in shear rate, threw light on its typical non-Newtonian pseudoplastic behaviour. The cytotoxicity tests on human cervical cancer (HeLa) cell line was studied which showed the dextran is non-toxic and biocompatible, rendering it safe for drug delivery, tissue engineering and various other biomedical applications. PMID: 20444595 [PubMed - as supplied by publisher] | | |
| Adipocyte Transplantation and Stem Cells: Plastic Surgery Meets Regenerative Medicine.
May 7, 2010 at 7:59 AM
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| | Adipocyte Transplantation and Stem Cells: Plastic Surgery Meets Regenerative Medicine. Cell Transplant. 2010 May 4; Authors: Tremolada C, Palmieri G, Ricordi C The technologies for adipose tissue harvesting, processing and transplantation have substantially evolved in the past two decades. Clinically driven advancements have paralleled a significant improvement in the understanding of cellular, molecular and immunobiological events surrounding cell and tissue transplantation. These new mechanistic insights could be of assistance to better understand the mechanisms underlying some of the observed clinical improvements. In addition to plastic and reconstructive surgical applications, adipose tissue has become central to an increasing number of translational efforts involving adipose tissue derived progenitor cells. The growing interest in this area of research has brought to the exploration of many novel research and clinical applications that utilize adipose tissue grafting and/or progenitor/stem cell derived cell products obtained from this tissue source. Progenitor, endothelial and mesenchymal stem cells derived from ad! ipose tissue could therefore not only be central to plastic and reconstructive surgery applications, but also become the focus of an array of therapeutic solutions for many disease conditions, such as those affecting bone, cartilage, muscle, liver, kidney, cardiac, neural and the pancreas, expanding the possible indications and translational potential of tissue, cell based and regenerative medicine strategies. PMID: 20444320 [PubMed - as supplied by publisher] | | |
| Platelet-rich fibrin membranes as scaffolds for periosteal tissue engineering.
May 7, 2010 at 7:59 AM
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| | Platelet-rich fibrin membranes as scaffolds for periosteal tissue engineering. Clin Oral Implants Res. 2010 May;21(5):543-9 Authors: Gassling V, Douglas T, Warnke PH, Açil Y, Wiltfang J, Becker ST OBJECTIVES: Platelet-rich fibrin (PRF)-based membranes have been used for covering alveolar ridge augmentation side in several in vivo studies. Few in vitro studies on PRF and no studies using human periosteal cells for tissue engineering have been published. The aim is a comparison of PRF with the commonly used collagen membrane Bio-Gide as scaffolds for periosteal tissue engineering. MATERIAL AND METHODS: Human periosteal cells were seeded on membrane pieces (collagen [Bio-Gide] and PRF) at a density of 10(4) cells/well. Cell vitality was assessed by fluorescein diacetate (FDA) and propidium iodide (PI) staining, biocompatibility with the lactate dehydrogenase (LDH) test and proliferation level with the MTT, WST and BrdU tests and scanning electron microscopy (SEM). RESULTS: PRF membranes showed slightly inferior biocompatibility, as shown by the LDH test. The metabolic activity measured by the MTT and WST tests was higher for PRF than for collagen (BioGide). Th! e proliferation level as measured by the BrdU test (quantitative) and SEM examinations (qualitative) revealed higher values for PRF. CONCLUSION: PRF appears to be superior to collagen (Bio-Gide) as a scaffold for human periosteal cell proliferation. PRF membranes are suitable for in vitro cultivation of periosteal cells for bone tissue engineering. PMID: 20443805 [PubMed - in process] | | |
| Three-Dimensional Mineralization of Dense Nanofibrillar Collagen-Bioglass Hybrid Scaffolds.
May 7, 2010 at 7:59 AM
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| | Three-Dimensional Mineralization of Dense Nanofibrillar Collagen-Bioglass Hybrid Scaffolds. Biomacromolecules. 2010 May 5; Authors: Marelli B, Ghezzi CE, Barralet JE, Boccaccini AR, Nazhat SN Scaffolds for bone tissue engineering must meet a number of requirements such as biocompatibility, osteoconductivity, osteoinductivity, biodegradability, and appropriate biomechanical properties. A combination of type I collagen and 45S5 Bioglass may meet these requirements, however, little has been demonstrated on the effect of Bioglass on the potential of the collagen nanofibrillar three-dimensional mineralization and its influence on the structural and mechanical properties of the scaffolds. In this work, rapidly fabricated dense collagen-Bioglass hybrid scaffolds were assessed for their potential for immediate implantation. Hybrid scaffolds were conditioned, in vitro, in simulated body fluid (SBF) for up to 14 days and assessed in terms of changes in structural, chemical, and mechanical properties. MicroCT and SEM analyses showed a homogeneous distribution of Bioglass particles in the as-made hybrids. Mineralization was detected at day 1 in SBF, while ATR-FTIR! microscopy and XRD revealed the presence of hydroxyl-carbonated apatite on the surface and within the two hybrid scaffolds at days 7 and 14. FTIR and SEM confirmed that the triple helical structure and typical banding pattern of fibrillar collagen was maintained as a function of time in SBF. Principal component analysis executed on ATR-FTIR microscopy revealed that the mineralization extent was a function of both Bioglass content and conditioning time in SBF. Tensile mechanical analysis showed an increase in the elastic modulus and a corresponding decrease in strain at ultimate tensile strength (UTS) as imparted by mineralization of scaffolds as a function of time in SBF and Bioglass content. Change in UTS was affected by Bioglass content. These results suggested the achievement of a hybrid matrix potentially suitable for bone tissue engineering. PMID: 20443577 [PubMed - as supplied by publisher] | | |
| Response of intractable skin ulcers in recessive dystrophic epidermolysis bullosa patients to an allogeneic cultured dermal substitute.
May 7, 2010 at 7:59 AM
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| | Response of intractable skin ulcers in recessive dystrophic epidermolysis bullosa patients to an allogeneic cultured dermal substitute. Acta Derm Venereol. 2010 Mar;90(2):165-9 Authors: Sawamura D, Goto M, Homma E, Goto-Ohguchi Y, Aoyagi S, Akiyama M, Kuroyanagi Y, Shimizu H, Natsuga K Recessive dystrophic epidermolysis bullosa (RDEB) is an inherited skin disorder caused by mutations in the COL7A1 gene, which encodes collagen VII (COL7). Skin ulcers in RDEB patients are sometimes slow to heal. We describe here the therapeutic response of intractable skin ulcers in two patients with generalized RDEB to treatment with an allogeneic cultured dermal substitute (CDS). Skin ulcers in both patients epithelialized by 3-4 weeks after this treatment. Immunohistochemical studies demonstrated that the COL7 expression level remained reduced with respect to the control skin and that it did not differ significantly between graft-treated and untreated areas. Electron microscopy showed aberrant anchoring fibrils beneath the lamina densa of both specimens. In conclusion, CDS is a promising modality for treatment of intractable skin ulcers in patients with RDEB, even though it does not appear to increase COL7 expression. PMID: 20169300 [PubMed - indexed for MEDLINE] | | |
| Inhibition of tumor growth and angiogenesis by a lysophosphatidic acid antagonist in an engineered three-dimensional lung cancer xenograft model.
May 7, 2010 at 7:59 AM
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| | Inhibition of tumor growth and angiogenesis by a lysophosphatidic acid antagonist in an engineered three-dimensional lung cancer xenograft model. Cancer. 2010 Apr 1;116(7):1739-50 Authors: Xu X, Prestwich GD BACKGROUND:: We developed an engineered three-dimensional (3D) tumor xenograft model of nonsmall cell lung cancer (NSCLC) in nude mice, and we used this model to evaluate a dual-activity inhibitor of lysophosphatidic acid (LPA) biosynthesis and receptor activation. METHODS:: First, BrP-LPA, a pan-antagonist for 4 LPA receptors and inhibitor of the lyosphospholipase D activity of autotaxin, was examined for inhibition of cell migration and cell invasion by human NSCLC A549 cells. Second, A549 cells were encapsulated in 3D in 3 semisynthetic extracellular matrices (ECMs) based on chemically modified glycosaminoglycans, and injected subcutaneously in nude mice. Tumor volume and vascularity were determined as a function of semisynthetic ECMs composition. Third, engineered NSCLC xenografts were formed from A549 cells in either Extracel-HP or Matrigel, and mice were treated with 4 intraperitoneal injections of 3 mg/kg of BrP-LPA. RESULTS:: First, BrP-LPA inhibited cell ! migration and invasiveness of A549 cells in vitro. Second, tumor growth and microvessel formation for 3D encapsulated A549 cells in vivo in nude mice increased in the following order: buffer only < Extracel < Extracel-HP < Extracel-HP containing growth factorss plus laminin. Third, tumor volumes increased rapidly in both Matrigel and Extracel-HP encapsulated A549 cells, and tumor growth was markedly inhibited by BrP-LPA treatment. Finally, tumor vascularization was dramatically reduced in the A549 tumors treated with BrP-LPA. CONCLUSIONS:: Engineered A549 lung tumors can be created by 3D encapsulation in an ECM substitute with user controlled composition. The engineered tumors regress and lose vascularity in response to a dual activity inhibitor of the LPA signaling pathway. Cancer 2010. (c) 2010 American Cancer Society. PMID: 20143443 [PubMed - indexed for MEDLINE] | | |
| [Effect of acellular process on small intestinal submucosa cell residue and growth factor content]
May 7, 2010 at 7:59 AM
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| | [Effect of acellular process on small intestinal submucosa cell residue and growth factor content] Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi. 2010 Jan;24(1):94-9 Authors: Chen W, Li C, Wu S, Xie H, Luo J OBJECTIVE: To investigate the effect of machine-enzyme digestion method on the residual quantity of small intestinal submucosa (SIS) cell and the content of growth factors. METHODS: Fresh jejunum of pig within 4 hours after harvesting was prepared into SIS after machine digestion (removing placenta percreta, mucosa, and muscular layer), decrease, trypsinization, abstergent processing, and freeze drying. Samples were kept after every preparation step serving as groups A, B, C, D, and E, respectively (n=4 per group). And the fresh jejunum served as control group (group F, n=4). The histological alteration in each preparation process was reviewed with HE staining and scanning electron microscope (SEM). Nest-polymerase chain reaction (PCR) was used to determine the content of death associated protein 12 (DAP12), and enzyme-linked immunosorbent assay (ELISA) was applied to detect the content of vascular endothelial growth factor (VEGF), basic fibroblast growth factor (! bFGF), transforming growth factor beta (TGF-beta), tumor necrosis factor alpha (TNF-alpha). RESULTS: HE staining and SEM observation showed that there were residual cells in groups A and B, and there were no residual cells in groups C, D, and E. Nest-PCR test revealed the occurrence of DAP12 in each group. The contents of DAP12 in groups A, B, C, D, E, and F were (18.01 +/- 9.53), (11.87 +/- 2.35), (0.59 +/- 0.27), (0.29 +/- 0.05), (0.19 +/- 0.04), and (183.50 +/- 120.13) copy x 10(6)/cm2. The content of DAP12 in group F was significant higher than that of other groups (P < 0.05), groups A and B was higher than groups C, D, and E (P < 0.05), there were significant differences among groups C, D, and E (P < 0.05), and there was no significant difference between groups A and B (P > 0.05). The ELISA test showed the content of VEGF, bFGF, TGF-beta, and TNF-alpha in group A was significantly higher than that of groups B, C, D, and E (P < 0.05), and there was no sig! nificant difference among groups B, C, D, and E (P > 0.05).! CONCLUS ION: SIS prepared by simple mechanical method has more residual cells, while the machine-enzyme digestion method can effectively remove the cells and significantly reduce the DAP12 content. This approach can not obviously reduce the growth factor content in SIS. PMID: 20135981 [PubMed - indexed for MEDLINE] | | |
| [Repairing defects of rabbit articular cartilage and subchondral bone with biphasic scaffold combined bone marrow stromal stem cells]
May 7, 2010 at 7:59 AM
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| | [Repairing defects of rabbit articular cartilage and subchondral bone with biphasic scaffold combined bone marrow stromal stem cells] Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi. 2010 Jan;24(1):87-93 Authors: Liu M, Xiang Z, Pei F, Huang F, Cen S, Zhong G, Fan H, Xiao Y, Sun J, Gao Y OBJECTIVE: To explore the preparing methods in vitro and test the clinical applicability of implantation in vivo of bone marrow stromal stem cells (BMSCs)-biphasic scaffold to repair defects of cartilage and subchondral bone and to compare the differences in repaired outcomes of composite, single biphasic scaffold and rabbits themselves. METHODS: The upper chondral phase and the lower osseous phase of the plugs, using poly-lactic-co-glycolic acid (PLGA), hydroxyapatite (HA), and other biomaterials, were fused into carrier scaffold, on which collagen type I (Col I) was coated. The surface and inner structure of biphasic scaffold were observed under scanning electron microscope (SEM). BMSCs was isolated from the bone marrow of tibia and femurs of young New Zealand rabbits using centrifuging and washing, and their morphologies and adherences were observed everyday. Then BMSCs were inoculated on the surface of scaffold to form BMSCs-scaffold composites. Osteochondral ! defects were surgically created on articular surface of femoral intercondylar of 30 New Zealand rabbits, which were divided into groups A, B and C. In group A, a biphasic osteochondral composite were implanted into defect, BMSCs and biphasic cylindrical porous plug of PLGA-HA-Col I in group B, and group C was used as a control without implant. Specimens were harvested to make macroscopic and histological observations at the 1st, 3rd, 6th, and 9th months after operation respectively; meanwhile immunohistological and micro-computed tomography (micro CT) examinations were performed and graded at the 9th month after operation. RESULTS: SEM showed an excellent connection of holes in the biphasic scaffold infiltrated by Col I. Optical microscopy and SEM showed a good growth of BMSCs in scaffold without obvious cellular morphological changes and an accumulation in the holes. Macroscopic samples showed a resistant existence of defects of group C within 9 months; the scaffold comple! tely degenerated and chondral-like tissue formed on articular ! surface with partly collapses and irregular defects in group A; and smoother surface without collapses and approach to normal with texture of new regeneration in group B. There were statistically significant differences in macroscopic results (P < 0.001), group B was superior to group A, and group C was the worst. The micro CT showed good repairs and reconstruction of subchondral bone, with a acceptable integration with newborn chondral-like tissue and host bone in group B. Quantificational analysis of relevant parameters showed no significant differences. Histological results showed inflammations located in defects at the 1st month, new tissue grew into scaffold at the 3rd month; new chondral-like tissue crept on the margin of defects and biphasic scaffold degenerated completely at the 6th month, and lots of collagen formed in subchondral bone with major fibrocartilage on chondral area at the 9th month after surgery in groups A and B. In groups A and B, immunohistological observ! ations were weak positive for Col II and positive for Col I. CONCLUSION: Biphasic scaffold implanted in body can induce and accelerate repair of defects of articular cartilages which are mainly filled with fibrocartilage, especially for subchondral bone. Scaffold combined with BMSCs has the best repairing effects 9 months after implantation. PMID: 20135980 [PubMed - indexed for MEDLINE] | | |
| Functional adiponectin resistance at the level of the skeletal muscle in mild to moderate chronic heart failure.
May 7, 2010 at 7:59 AM
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| | Functional adiponectin resistance at the level of the skeletal muscle in mild to moderate chronic heart failure. Circ Heart Fail. 2010 Mar;3(2):185-94 Authors: Van Berendoncks AM, Garnier A, Beckers P, Hoymans VY, Possemiers N, Fortin D, Martinet W, Van Hoof V, Vrints CJ, Ventura-Clapier R, Conraads VM BACKGROUND: Adiponectin is an antiinflammatory, insulin-sensitizing, and antiatherogenic adipocytokine that plays a fundamental role in energy homeostasis. In patients with chronic heart failure (CHF), high circulating adiponectin levels are associated with inverse outcome. Recently, adiponectin expression has been identified in human skeletal muscle fibers. We investigated the expression of adiponectin, the adiponectin receptors, and genes involved in the downstream lipid and glucose metabolism in the skeletal muscle of patients with CHF. METHODS AND RESULTS: Muscle biopsies (vastus lateralis muscle) were obtained from 13 patients with CHF and 10 healthy subjects. mRNA transcript levels of adiponectin, adiponectin receptors (AdipoR1 and AdipoR2), and downstream adiponectin-related enzymes were quantified by real-time reverse transcriptase polymerase chain reaction. Adiponectin expression in the skeletal muscle of patients with CHF was 5-fold higher than in health! y subjects (P<0.001), whereas AdipoR1 was downregulated (P=0.005). In addition, the expression of the main genes involved in downstream pathway (peroxisome proliferator-activated receptor-alpha [PPAR-alpha] and both AMP-activated protein kinase-alpha1 and -alpha2 subunits) as well as their target genes in lipid (acyl-coenzyme A dehydrogenase C-14 to C-12 straight chain) and glucose metabolism (hexokinase-2) were significantly reduced in CHF. The strong positive correlation found between AdipoR1 and PPAR-alpha/AMP-activated protein kinase gene expression was confirmed in PPAR-alpha null mice, suggesting a cause-and-effect relationship. Immunohistochemical staining confirmed the presence of adiponectin in the skeletal muscle. CONCLUSIONS: Despite increased adiponectin expression in the skeletal muscle, patients with CHF are characterized by downregulation of AdipoR1 that is most probably linked to deactivation of the PPAR-alpha/AMP-activated protein kinase pathway. These f! acts suggest functional adiponectin resistance at the level of! the ske letal muscle in CHF. PMID: 20103776 [PubMed - indexed for MEDLINE] | | |
| [Exploratory study on the micro-remodeling of dermal tissue]
May 7, 2010 at 7:59 AM
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| | [Exploratory study on the micro-remodeling of dermal tissue] Zhonghua Shao Shang Za Zhi. 2009 Oct;25(5):343-50 Authors: Jiang YZ, Ding GF, Lu SL OBJECTIVE: To explore the effect of three-dimensional structure of dermal matrix on biological behavior of fibroblasts (Fb) in the microcosmic perspective. METHODS: The three-dimensional structure of dermal tissue was analyzed by plane geometric and trigonometric function. Microdots structure array with cell adhesion effect was designed by computer-assisted design software according to the adhesive and non-adhesive components of dermal tissue. Four sizes (8 microm x 3 microm, space 6 microm; 16 microm x 3 microm, space 6 microm; 16 microm x 5 microm, space 8 microm; 20 microm x 3 microm, space 2 microm) of micropier grid used for cell culture (MPGCC) with cell-adhesive microdots, built up with micro-pattern printing and molecule self-assembly method were used to culture dermal Fb. Fb cultured with cell culture matrix without micropier grid was set up as control. The expression of skeleton protein (alpha-SMA) of Fb, cell viability and cell secretion were detected w! ith immunohistochemistry, fluorescent immunohistochemistry, MTT test and the hydroxyproline content assay. RESULTS: The three-dimensional structure of dermal tissue could be simulated by MPGCC as shown in arithmetic analysis. Compared with those of control group [(12 +/- 3)% and (0.53 +/- 0.03) microg/mg, (0.35 +/- 0.04)], the expression of alpha-SMA [(49 +/- 3)%, (61 +/- 3)%, (47 +/- 4)%, (51 +/- 3)%] and the content of hydroxyproline [(0.95 +/- 0.04), (0.87 +/- 0.03), (0.81 +/- 0.03), (0.77 +/- 0.03) microg/mg] were increased significantly (P < 0.05), the cell viability of Fb (0.12 +/- 0.03, 0.13 +/- 0.04, 0.14 +/- 0.03, 0.19 +/- 0.03) cultured in MPGCC was decreased significantly (P < 0.05). When the parameters of micropier grid were changed, the expression of alpha-SMA, the cell viability and the content of hydroxyproline of Fb cultured in four sizes of MPGCC were also significantly changed as compared with one another (P < 0.05). CONCLUSIONS: MPGCC may be the ! basic functional unit of dermal template, or unit of dermal te! mplate t o call. Different three-dimensional circumstances for dermal tissue can result in different template effect and wound healing condition. PMID: 19951556 [PubMed - indexed for MEDLINE] | | |
| [Morphological observation of human keratinocytes tridimensionally cocultured with xenogenic acellular dermal matrix]
May 7, 2010 at 7:59 AM
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| | [Morphological observation of human keratinocytes tridimensionally cocultured with xenogenic acellular dermal matrix] Zhonghua Shao Shang Za Zhi. 2009 Aug;25(4):258-60 Authors: ZHU CT, PENG DZ, WANG LH, HE B, ZHENG BX, ZHOU X, LUO HS, WANG Y, LIU J OBJECTIVE: To establish the tridimensional culture method for tissue-engineered skin to observe the histomorphological change in human immortal KC strain (HacaT)cocultured with xenogenic acellular dermal matrix (ADM). METHODS: The ADM was prepared from SD rats by a modified method. HaCaTs were cultured in defined KC-serum free medium. HaCaTs in log growth phase were inoculated on ADM at the cell density of 2 x 10(5)/cm(2). They were submergedly cultured for 5 days and then changed to air-liquid phase culture for another 5 days. ADM and growth of HaCaTs on day 1 and 5 after cocultured with ADM were observed with scanning electron microscope. The histological change in ADM and HaCaTs on day 1, 5, and 10 after cocultured with ADM were examined by HE staining. RESULTS: The gross appearance of ADM was white with smooth and soft texture, and intact collagen bundles without cellular residue. HaCaTs adhered and stretched out pseudopodia on the surface of the ADM on day 1 ! after combined culture, and a monolayer of cells was formed on day 5, growing into 3-6 layers of cells on day 10 with a tendency to grow into ADM. CONCLUSIONS: SD rats ADM is benefit for the adhesion of HaCaTs and the permeation of nutrient solution, from which an engineered multiple-layered human skin can be obtained within 10 days. PMID: 19951542 [PubMed - indexed for MEDLINE] | | |
| Gef gene therapy enhances the therapeutic efficacy of doxorubicin to combat growth of MCF-7 breast cancer cells.
May 7, 2010 at 7:59 AM
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| | Gef gene therapy enhances the therapeutic efficacy of doxorubicin to combat growth of MCF-7 breast cancer cells. Cancer Chemother Pharmacol. 2010 May;66(1):69-78 Authors: Prados J, Melguizo C, Rama AR, Ortiz R, Segura A, Boulaiz H, Vélez C, Caba O, Ramos JL, Aránega A PURPOSE: The potential use of combined therapy is under intensive study including the association between classical cytotoxic and genes encoding toxic proteins which enhanced the antitumour activity. The main aim of this work was to evaluate whether the gef gene, a suicide gene which has a demonstrated antiproliferative activity in tumour cells, improved the antitumour effect of chemotherapeutic drugs used as first-line treatment in the management of advanced breast cancer. METHODS: MCF-7 human breast cancer cells were transfected with gef gene using pcDNA3.1-TOPO expression vector. To determine the effect of the combined therapy, MCF-7 transfected and non-transfected cells were exposed to paclitaxel, docetaxel and doxorubicin at different concentrations. The growth-inhibitory effect of gef gene and/or drugs was assessed by MTT assay. Apoptosis modulation was determined by flow cytometric analysis, DNA fragmentation and morphological analysis. Multicellular tumour! spheroids (MTS) from MCF-7 cells were used to confirm effectiveness of combined therapy (gef gene and drug). RESULTS: Our results demonstrate that combined therapy gef gene/drugs (paclitaxel, docetaxel or doxurubicin) caused a decrease in cell viability. However, only the gef-doxorubicin (10 microM) combination induced a greater enhancement in the antitumour activity in MCF-7 cells. Most importantly, this combined strategy resulted in a significant synergistic effect, thus allowing lower doses of the drug to be used to achieve the same therapeutic effect. These results were confirmed using MTS in which volume decrease with combined therapy was greater than obtained using the gene therapy or chemotherapy alone, or the sum of both therapies. CONCLUSIONS: The cytotoxic effect of gef gene in breast cancer cells enhances the chemotherapeutic effect of doxorubicin. This therapeutic approach has the potential to overcome some of the major limitations of conventional chemotherapy,! and may therefore constitute a promising strategy for future ! applicat ions in breast cancer therapy. PMID: 19771430 [PubMed - indexed for MEDLINE] | | |
| Nanomechanical characterization of tissue engineered bone grown on titanium alloy in vitro.
May 7, 2010 at 7:59 AM
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| | Nanomechanical characterization of tissue engineered bone grown on titanium alloy in vitro. J Mater Sci Mater Med. 2010 Jan;21(1):277-82 Authors: Chen J, Birch MA, Bull SJ Intensive work has been performed on the characterization of the mechanical properties of mineralised tissues formed in vivo. However, the mechanical properties of bone-like tissue formed in vitro have rarely been characterised. Most research has either focused on compact cortical bone or cancellous bone, whilst leaving woven bone unaddressed. In this study, bone-like mineralised matrix was produced by osteoblasts cultured in vitro on the surface of titanium alloys. The volume of this tissue-engineered bone is so small that the conventional tensile tests or bending tests are implausible. Therefore, nanoindentation techniques which allow the characterization of the test material from the nanoscale to the microscale were adopted. These reveal the apparent elastic modulus and hardness of the calcospherulite crystals (a representative element for woven bone) are 2.35 +/- 0.73 and 0.41 +/- 0.15 GPa, respectively. The nanoscale viscoelasticity of such woven bone was fur! ther assessed by dynamic indentation analysis. PMID: 19669624 [PubMed - indexed for MEDLINE] | | |
| Microfluidic synthesis of pure chitosan microfibers for bio-artificial liver chip.
May 7, 2010 at 7:59 AM
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| | Microfluidic synthesis of pure chitosan microfibers for bio-artificial liver chip. Lab Chip. 2010 May 21;10(10):1328-34 Authors: Lee KH, Shin SJ, Kim CB, Kim JK, Cho YW, Chung BG, Lee SH We developed microfluidic-based pure chitosan microfibers ( approximately 1 meter long, 70-150 mum diameter) for liver tissue engineering applications. Despite the potential of the chitosan for creating bio-artificial liver chips, its major limitation is the inability to fabricate pure chitosan-based microstructures with controlled shapes because of the mechanical weakness of the pure chitosan. Previous studies have shown that chitosan micro/nanofibers can be fabricated by using chemicals and electrospinning techniques. However, there is no paper regarding pure chitosan-based microfibers in a microfluidic device. This paper suggests a unique method to fabricate pure chitosan microfibers without any chemical additive. We also analyzed the chemical, mechanical, and diffusion properties of pure chitosan microfibers. Attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectrometry and electron spectroscopy for chemical analysis (ESCA) were used to analyz! e the chemical composition of the synthesized chitosan microfibers. We measured the mechanical axial-force and diffusion coefficient in pure chitosan-based microfibers using fluorescence recovery after photobleaching (FRAP) techniques. Furthermore, to evaluate the capability of the microfibers for liver tissue formation, hepatoma HepG2 cells were seeded onto the chitosan microfibers. The functionality of these hepatic cells cultured on chitosan microfibers was analyzed by measuring albumin secretion and urea synthesis. Therefore, this pure chitosan-based microfiber chip could be a potentially useful method for liver tissue engineering applications. PMID: 20445889 [PubMed - in process] | | | | 
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