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| Fomer Top Exec at CIRM Hired by San Diego Firm
March 17, 2010 at 1:04 PM
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| The former chief scientific officer for the California stem cell agency, Marie Csete, has landed at a San Diego firm, where she has been named executive vice president for research and development.
Csete resigned from her state government post last June, creating a bit of a stir. She told Nature magazine that her advice was not respected at the $3 billion stem cell agency.
Csete has joined | | |
| Membrane vesicles containing matrix metalloproteinase-9 and fibroblast growth factor-2 are released into the extracellular space from mouse mesoangioblast stem cells.
March 17, 2010 at 8:33 AM
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| | Membrane vesicles containing matrix metalloproteinase-9 and fibroblast growth factor-2 are released into the extracellular space from mouse mesoangioblast stem cells. J Cell Physiol. 2010 Mar 15; Authors: Candela ME, Geraci F, Turturici G, Taverna S, Albanese I, Sconzo G Certain proteins, including fibroblast growth factor-2 (FGF-2) and matrix metalloproteinase-9 (MMP-9), have proved very effective in increasing the efficacy of mesoangioblast stem cell therapy in repairing damaged tissue. We provide the first evidence that mouse mesoangioblast stem cells release FGF-2 and MMP-9 in their active form through the production of membrane vesicles. These vesicles are produced and turned over continuously, but are stable for some time in the extracellular milieu. Mesoangioblasts shed membrane vesicles even under oxygen tensions that are lower than those typically used for cell culture and more like those of mouse tissues. These findings suggest that mesoangioblasts may themselves secrete paracrine signals and factors that make damaged tissues more amenable to cell therapy through the release of membrane vesicles. J. Cell. Physiol. (c) 2010 Wiley-Liss, Inc. PMID: 20232295 [PubMed - as supplied by publisher] | | |
| Proteomic analysis of human mesenchymal stromal cells derived from adipose tissue undergoing osteoblast differentiation.
March 17, 2010 at 6:58 AM
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| | Proteomic analysis of human mesenchymal stromal cells derived from adipose tissue undergoing osteoblast differentiation. Cytotherapy. 2010 Mar 15; Authors: Giusta MS, Andrade H, Santos AV, Castanheira P, Lamana L, Pimenta AM, Goes AM Abstract Background aims. Stem cells derived from human adipose tissue (ASC) have the capacity for renewal, are easily obtained and have plasticity properties that allow them to differentiate into several cell types, including osteoblast cells. With the aim of understanding the issue of the osteogenic process and finding reliable biomarkers in cells undergoing the osteogeneic differentiation process, this work took advantage of a proteomic approach to identify proteins involved in osteogenesis. Methods. For this purpose, ASC were analyzed under three conditions: S0, in the absence of stimulation; S1, with 2 weeks of osteogenic medium stimulation; and S2, with 4 weeks of osteogenic medium stimulation. The identification of ASC was carried out by flow cytometry using antibodies specific to known undifferentiated stem cell-surface markers. Cell viability, enzymatic activity, mineral deposition, collagen structure and production and gene analyzes were evaluated for ea! ch condition. Results. Phenotypic modifications were observed during the in vitro osteogenic differentiation process by two-dimensional (2-D) differential image gel electrophoresis (DIGE). The proteins were identified by mass espectrometry in tandem (MS/MS) analyzes using Matrix-assisted laser desorption/ionization with TOF/TOF is a tandem mass spectrometry method where two time-of-flight mass spectrometers are used consecutively (MALDI-TOF/TOF). A total of 51 differentially expressed proteins was identified when comparing the three observed conditions. Sixteen different spots were identified in the S0 stage compared with S2, while 28 different spots were found in S2 compared with S0. S1 expressed seven different spots compared with S0 and S2. Conclusions. These findings suggest the involvement of several proteins directly related to the osteogenic pathway, which can be used to improve understanding of the osteogenic process. PMID: 20230220 [PubMed - as supplied by publisher] | | |
| Effect of encapsulation or grafting on release kinetics of recombinant human bone morphogenetic protein-2 from self-assembled poly(lactide-co-glycolide ethylene oxide fumarate) nanoparticles.
March 17, 2010 at 6:35 AM
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| | Effect of encapsulation or grafting on release kinetics of recombinant human bone morphogenetic protein-2 from self-assembled poly(lactide-co-glycolide ethylene oxide fumarate) nanoparticles. Microsc Res Tech. 2010 Mar 15; Authors: Mercado AE, Jabbari E The objective of this work was to compare the release characteristics of Recombinant human bone morphogenetic protein-2 (rhBMP-2) encapsulated in thermally self-assembled poly(lactide ethylene oxide fumarate) (PLEOF) nanoparticles (NPs) with rhBMP-2 grafted to succinimide-terminated poly(lactide fumarate) (PLAF-NHS) or poly(lactide-co-glycolide fumarate) (PLGF-NHS) NPs. The amphiphilic PLEOF NPs had average size of 110 +/- 50 nm. The hydrophobic PLAF-NHS and PLGF-NHS NPs had average size of 242 +/- 67 and 195 +/- 42 nm, respectively. PLEOF NPs had rhBMP-2 encapsulation efficiency ranging from 65 to 93%. Grafting efficiency of rhBMP-2 to PLAF-NHS and PLGF-NHS NPs was 97% +/- 1% and 98% +/- 1%, respectively. PLEOF NPs displayed a relatively high-release rate of rhBMP-2 in the first week, which rapidly dropped to zero after 10 days. PLEOF NPs grafted with 10 and 20 mug/mL rhBMP-2 released 67 and 80% of the protein in the active conformation after degradation. PLGF-NH! S NPs displayed sustained release of rhBMP-2 in the first 2 weeks but dropped to almost zero rate (<3 ng/day) after 20 days. PLAF-NHS NPs showed the longest period of sustained release of active rhBMP-2 at two rates: a high rate of 25-35 ng/mL in the first 2 weeks followed by a low rate of 5-10 ng/mL from 2 to 6 weeks. Nearly, 25 and 50% of the rhBMP-2 released from PLGF-NHS and PLAF-NHS NPs, respectively, were enzymatically active after degradation of the NPs. PLEOF NPs provided a fast release of rhBMP-2 for 1 week, whereas PLAF-NHS NPs provided a slow release for up to 6 weeks. Microsc. Res. Tech., 2010. (c) 2010 Wiley-Liss, Inc. PMID: 20232367 [PubMed - as supplied by publisher] | | |
| Structural and cellular features in metaphyseal and diaphyseal periosteum of osteoporotic rats.
March 17, 2010 at 6:35 AM
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| | Structural and cellular features in metaphyseal and diaphyseal periosteum of osteoporotic rats. J Mol Histol. 2010 Mar 16; Authors: Fan W, Bouwense SA, Crawford R, Xiao Y Despite the important physiological role of periosteum in the pathogenesis and treatment of osteoporosis, little is known about the structural and cellular characteristics of periosteum in osteoporosis. To study the structural and cellular differences in both diaphyseal and metaphyseal periosteum of osteoporotic rats, samples from the right femur of osteoporotic and normal female Lewis rats were collected and tissue sections were stained with hematoxylin and eosin, antibodies or staining kit against tartrate resistant acid phosphatase (TRAP), alkaline phosphatase (ALP), vascular endothelial growth factor (VEGF), von Willebrand (vWF), tyrosine hydroxylase (TH) and calcitonin gene-related peptide (CGRP). The results showed that the osteoporotic rats had much thicker and more cellular cambial layer of metaphyseal periosteum compared with other periosteal areas and normal rats (P < 0.001). The number of TRAP(+) osteoclasts in bone resorption pits, VEGF(+) cells and! the degree of vascularization were found to be greater in the cambial layer of metaphyseal periosteum of osteoporotic rats (P < 0.05), while no significant difference was detected in the number of ALP(+) cells between the two groups. Sympathetic nerve fibers identified by TH staining were predominantly located in the cambial layer of metaphyseal periosteum of osteoporotic rats. No obvious difference in the expression of CGRP between the two groups was found. In conclusion, periosteum may play an important role in the cortical bone resorption in osteoporotic rats and this pathological process may be regulated by the sympathetic nervous system. PMID: 20232237 [PubMed - as supplied by publisher] | | |
| Electro-spinning of PLGA/PCL blends for tissue engineering and their biocompatibility.
March 17, 2010 at 6:35 AM
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| | Electro-spinning of PLGA/PCL blends for tissue engineering and their biocompatibility. J Mater Sci Mater Med. 2010 Mar 16; Authors: Hiep NT, Lee BT In this study, an electro-spun co-polymer PLGA/PCL blend was fabricated using various percentages of PLGA in the blend PLGA/PCL solutions. The PLGA/PCL ratios used to fabricate the electrospun fibrous mats were reflected in the FT-IR (Fourier Transform Infrared Spectroscopy) data. Experimental results from the MTT assay showed that the biocompatibility of the electro-spun co-polymer increased at increasing percentages of PLGA. In vitro cells adhesion and proliferation of fibroblast cells on electro-spun mats were characterized by SEM morphology. In addition, we found that increasing PLGA concentrations affected the mechanical properties of electro-spun membranes and increased the biocompatibility of PLGA/PCL electro-spun fibrous mats. PMID: 20232234 [PubMed - as supplied by publisher] | | |
| Preparation and characterization of collagen microspheres for sustained release of VEGF.
March 17, 2010 at 6:35 AM
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| | Preparation and characterization of collagen microspheres for sustained release of VEGF. J Mater Sci Mater Med. 2010 Mar 16; Authors: Nagai N, Kumasaka N, Kawashima T, Kaji H, Nishizawa M, Abe T In this study, we prepared injectable collagen microspheres for the sustained delivery of recombinant human vascular endothelial growth factor (rhVEGF) for tissue engineering. Collagen solution was formed into microspheres under a water-in-oil emulsion condition, followed by crosslinking with water-soluble carbodiimide. Various sizes of collagen microspheres in the range of 1-30 mum diameters could be obtained by controlling the surfactant concentration and rotating speed of the emulsified mixture. Particle size proportionally decreased with increasing the rotating speed (1.8 mum per 100 rpm increase in the range of 300-1,200 rpm) and surfactant concentration (3.1 mum per 0.1% increase in the range of 0.1-0.5%). The collagen microspheres showed a slight positive charge of 8.86 and 3.15 mV in phosphate-buffered saline and culture medium, respectively. Release study showed the sustained release of rhVEGF for 4 weeks. Released rhVEGF was able to induce capillary form! ation of human umbilical vein endothelial cells, indicating the maintenance of rhVEGF bioactivity after release. In conclusion, the results suggest that the collagen microspheres have potential for sustained release of rhVEGF. PMID: 20232232 [PubMed - as supplied by publisher] | | |
| Why we need semisolid decalcification system in bone tissue engineering? A story begins with honeycomb.
March 17, 2010 at 6:35 AM
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| | Why we need semisolid decalcification system in bone tissue engineering? A story begins with honeycomb. Med Hypotheses. 2010 Mar 13; Authors: Jiang S, Jiang QL, Zhang Y, Li L, Zhao PR, Pan YF, Chang W, Liu LJ, Pei GX The repair of large segmental bone defects remains a tough problem disturbing surgeons and researchers. Bone tissue engineering brings some new sight in this field. However, it has not been effectively applied in clinics, for the reason that the involved mechanism is not well understood. Thus, we need to know the osteogenesis process of the tissue-engineered bone including distribution, proliferation and interaction among seed cells pre-inoculated in biomaterials as well as the function of surrounding tissues. As a matter of fact, the tissue-engineered bone or the biomaterials are solid and opaque, which makes the study difficult. Here, inspired by the structure of honeycomb and amber, we hypothesize a semisolid decalcification protocol to solve this problem. PMID: 20231059 [PubMed - as supplied by publisher] | | |
| [Effects of UO-126 on proliferation and fbw7 expression of HeLa cells.]
March 17, 2010 at 6:35 AM
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| | [Effects of UO-126 on proliferation and fbw7 expression of HeLa cells.] Xi Bao Yu Fen Zi Mian Yi Xue Za Zhi. 2010 Feb;26(2):138-40 Authors: Sun D, Shen Y, Wang SH, Xiang ZW, Xie YS, Jiang X AIM: To observe the effects of UO-126 on the expression of F-box and WD repeat domain-containing protein 7(FBW7)and on the proliferation of human Cervical cancer cell lines (HeLa cells). METHODS: HeLa cells were treated with different concentrations of UO-126, MTT assay was used to observe the proliferation of HeLa cells.Immunofluorescence showed the lacation and expression of FBW7 in HeLa cells.The mRNA and protein expression of FBW7 were detected by RT-PCR and Western blot before and after mitogen-activated protein kinases (MAPK)signal was blocked by UO-126 a MAPK inhibitor. RESULTS: MTT results showed that the concentration range of MAPK signaling pathway inhibitor UO-126 inhibited the proliferation of HeLa cells in a concentration-and time-dependent manner(P<0.05). Immunofluorescence showed that the expression of positive FBW7 had increased after HeLa cells were treated with UO-126. RT-PCR and Western blot exhibited that the FBW7 mRNA and protein expression! had significantly increased before and after HeLa cells were treated with UO-126(P<0.05). CONCLUSION: UO-126 could inhibit HeLa cells proliferation, FBW7 lied downstream of MAPK signaling pathway. PMID: 20230673 [PubMed - in process] | | |
| Curcumin Prevents Dopaminergic Neuronal Death Through Inhibition of the c-Jun N-Terminal Kinase Pathway.
March 17, 2010 at 6:35 AM
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| | Curcumin Prevents Dopaminergic Neuronal Death Through Inhibition of the c-Jun N-Terminal Kinase Pathway. Rejuvenation Res. 2010 Feb;13(1):55-64 Authors: Yu S, Zheng W, Xin N, Chi ZH, Wang NQ, Nie YX, Feng WY, Wang ZY Abstract Recent studies have shown that the c-Jun N-terminal kinase (JNK) signaling pathway is involved in dopaminergic neuronal degeneration, and direct blockade of JNK by specific inhibitors may prevent or effectively slow the progression of Parkinson disease (PD). Previous studies have revealed that the natural phenolic compound curcumin can reduce inflammation and oxidation, which makes it a potential therapeutic agent for neurodegenerative diseases. In this study, we investigated whether curcumin protects against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine- (MPTP) or 1-methyl-4-phenylpyridnium ion- (MPP(+)) induced dopaminergic neurotoxicity in C57BL/6N mice or SH-SY5Y cells by inhibiting JNK pathways both in vivo and in vitro. Curcumin treatment significantly improved behavioral deficits, and enhanced the survival of tyrosine hydroxylase-positive neurons in the substantia nigra (SN) in the MPTP-induced PD model mice. Most importantly, curcumin treatment sig! nificantly inhibited MPTP/MPP(+)-induced phosphorylation of JNK1/2 and c-Jun, and cleaved caspase-3. Our study suggests that the neuroprotective effect of curcumin is not related simply to its antiinflammatory and antioxidant properties, but involves other mechanisms, particularly by targeting the JNK pathways. PMID: 20230279 [PubMed - in process] | | |
| Establishment of immortalized mesenchymal stromal cells with red fluorescence protein expression for in vivo transplantation and tracing in the rat model with traumatic brain injury.
March 17, 2010 at 6:35 AM
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| | Establishment of immortalized mesenchymal stromal cells with red fluorescence protein expression for in vivo transplantation and tracing in the rat model with traumatic brain injury. Cytotherapy. 2010 Mar 15; Authors: Hung CJ, Yao CL, Cheng FC, Wu ML, Wang TH, Hwang SM Abstract Background aims. Human mesenchymal stromal cells (hMSC) play a crucial role in tissue engineering and regenerative medicine, and have important clinical potential for cell therapy. However, many hMSC studies have been restricted by limited cell numbers and difficult detection in vivo. To expand the lifespan, hMSC are usually immortalized by virus-mediated gene transfer. However, these genetically modified cells easily lose critical phenotypes and stable genotypes because of insertional mutagenesis. Methods. We used a non-viral transfection method to establish human telomerase reverse transcriptase-immortalized cord blood hMSC (hTERT-cbMSC). We also established red fluorescent protein (RFP)-expressing hTERT-cbMSC (hTERT/RFP-cbMSC) by the same non-viral transfection method, and these cells were injected into a rat model with traumatic brain injury for in vivo detection analysis. Results. The hTERT-cbMSC could grow more than 200 population doublings with a s! table doubling time and maintained differentiation capacities. hTERT/RFP-cbMSC could proliferate efficiently within 2 weeks at the injury location and could be detected easily under a fluorescent microscope. Importantly, both hTERT-cbMSC and hTERT/RFP-cbMSC showed no chromosomal abnormalities by karyotype analysis and no tumor formation in severe combined immunodeficient (SCID) mice by transplantation assay. Conclusions. We have developed immortalized cbMSC with hTERT expression and RFP expression, which will be useful tools for stem cell research and translational study. PMID: 20230225 [PubMed - as supplied by publisher] | | |
| Bio-electrospraying: a potentially safe technique for delivering progenitor cells.
March 17, 2010 at 6:35 AM
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| | Bio-electrospraying: a potentially safe technique for delivering progenitor cells. Biotechnol Bioeng. 2010 Mar 12; Authors: Sahoo S, Lee WC, Goh JC, Toh SL Bio-electrospraying is fast becoming an attractive tool for in situ cell delivery into scaffolds for tissue engineering applications, with several cell types been successfully electrosprayed. Bone marrow derived mesenchymal progenitor/stem cells (BMSC), which are an important cell source for tissue engineering, have not been explored in detail and the effect of electrospraying on their "stemness" is not known. This study therefore investigates the effects of electrospraying on BMSC viability, proliferation and multilineage differentiation potential. Electrospraying a BMSC suspension at flow rate of 6 ml/hr and voltages of 7.5 - 15 kV could successfully generate a continuous, stable and linearly directed electrospray of cells. Morphological observation, trypan blue tests and alamar blue based metabolic assays revealed about 88% of these electrosprayed cells were viable, and proliferated at rates similar to native BMSCs. However, at higher voltages, electrospraying ! became unstable and reduced cell viability, possibly due to electrical or thermal damage to the cells. BMSCs electrosprayed at 7.5 kV also retained their multipotency and could be successfully differentiated into adipogenic, chondrogenic and osteogenic lineages, demonstrating similar morphology and gene expression levels as induced native BMSCs. These results indicate that bio-electrospraying could be safely used as a progenitor/stem cell delivery technique for tissue engineering and regenerative medicine applications. (c) 2010 Wiley Periodicals, Inc. PMID: 20229515 [PubMed - as supplied by publisher] | | |
| Three-dimensional tissue culture based on magnetic cell levitation.
March 17, 2010 at 6:35 AM
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| | Three-dimensional tissue culture based on magnetic cell levitation. Nat Nanotechnol. 2010 Mar 14; Authors: Souza GR, Molina JR, Raphael RM, Ozawa MG, Stark DJ, Levin CS, Bronk LF, Ananta JS, Mandelin J, Georgescu MM, Bankson JA, Gelovani JG, Killian TC, Arap W, Pasqualini R Cell culture is an essential tool in drug discovery, tissue engineering and stem cell research. Conventional tissue culture produces two-dimensional cell growth with gene expression, signalling and morphology that can be different from those found in vivo, and this compromises its clinical relevance. Here, we report a three-dimensional tissue culture based on magnetic levitation of cells in the presence of a hydrogel consisting of gold, magnetic iron oxide nanoparticles and filamentous bacteriophage. By spatially controlling the magnetic field, the geometry of the cell mass can be manipulated, and multicellular clustering of different cell types in co-culture can be achieved. Magnetically levitated human glioblastoma cells showed similar protein expression profiles to those observed in human tumour xenografts. Taken together, these results indicate that levitated three-dimensional culture with magnetized phage-based hydrogels more closely recapitulates in vivo pro! tein expression and may be more feasible for long-term multicellular studies. PMID: 20228788 [PubMed - as supplied by publisher] | | |
| Comparative Expression Profiles of mRNAs and microRNAs Among Human Mesenchymal Stem Cells Derived From Breast, Face, and Abdominal Adipose Tissues.
March 17, 2010 at 6:35 AM
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| | Comparative Expression Profiles of mRNAs and microRNAs Among Human Mesenchymal Stem Cells Derived From Breast, Face, and Abdominal Adipose Tissues. Kaohsiung J Med Sci. 2010 Mar;26(3):113-122 Authors: Wang KH, Kao AP, Singh S, Yu SL, Kao LP, Yun Tsai Z, Lin SD, Li SS We determined the expression of both mRNAs and microRNAs (miRNAs) from human mesenchymal stem cells BM19, FM30, and AM3, which is derived from breast, face, and abdominal adipose tissues, respectively. BM19, FM30, and AM3 cells exhibited considerably similar mRNA profiles, and their 1,038 abundantly common genes were involved in regulating six cell adhesion and three cytoskeleton remodeling processes among the top ten GeneGo canonical pathway maps. The 39 most abundant miRNAs in AM3 cells were expressed at very similar levels in BM19 cells. However, seven abundant miRNAs (miR-19b, miR-320, miR-186, miR-199a, miR-339, miR-99a, and miR-152) in AM3 cells were expressed at much lower levels than that in FM30 cells, and 38 genes targeted by these miRNAs were consequently upregulated more than 3-fold in FM30 cells compared with AM3 cells. Therefore, autologous abdominal adipose-derived mesenchymal stem cells are suitable for tissue engineering of breast reconstruction b! ecause of very similar expression profiles of mRNAs and miRNAs between AM3 and BM19 cells. Conversely, abdominal AM3 cells might not be suitable for facial rejuvenation, since the 38 highly expressed genes targeted by miRNAs in FM30 cells might play an important role(s) in the development of facial tissue. PMID: 20227650 [PubMed - as supplied by publisher] | | |
| On stiffness of scaffolds for bone tissue engineering-a numerical study.
March 17, 2010 at 6:35 AM
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| | On stiffness of scaffolds for bone tissue engineering-a numerical study. J Biomech. 2010 Mar 11; Authors: Sturm S, Zhou S, Mai YW, Li Q Tissue scaffolds are typically designed and fabricated to match native bone properties. However, it is unclear if this would lead to the best tissue ingrowth outcome within the scaffold as neo-tissue keeps changing the stiffness of entire construct. This paper presents a numerical method to address this issue for design optimization and assessment of tissue scaffolds. The elasticity tensors of two different types of bones are weighted by different multipliers before being used as the targets in scaffold design. A cost function regarding the difference between the effective elasticity tensor, calculated by the homogenization technique, and the target tensor, is minimized by using topology optimization procedure. It is found that different stiffnesses can lead to different remodeling results. The comparison confirms that bone remodeling is at its best when the scaffold elastic tensor matches or is slightly higher than the elastic properties of the host bone. PMID: 20227080 [PubMed - as supplied by publisher] | | |
| Critical role of tissue mast cells in controlling long-term glucose sensor function in vivo.
March 17, 2010 at 6:35 AM
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| | Critical role of tissue mast cells in controlling long-term glucose sensor function in vivo. Biomaterials. 2010 Mar 10; Authors: Klueh U, Kaur M, Qiao Y, Kreutzer DL Little is known about the specific cells, mediators and mechanisms involved in the loss of glucose sensor function (GSF) in vivo. Since mast cells (MC) are known to be key effector cells in inflammation and wound healing, we hypothesized that MC and their products are major contributors to the skin inflammation and wound healing that controls GSF at sites of sensor implantation. To test this hypothesis we utilized a murine model of continuous glucose monitoring (CGM) in vivo in both normal C57BL/6 mice (mast cell sufficient), as well as mast cell deficient B6.Cg-Kit(W-sh)/HNihrJaeBsmJ (Sash) mice over a 28 day CGM period. As expected, both strains of mice displayed excellent CGM for the first 7 days post sensor implantation (PSI). CGM in the mast cell sufficient C57BL/6 mice was erratic over the remaining 21 days PSI. CGM in the mast cell deficient Sash mice displayed excellent sensor function for the entire 28 day of CGM. Histopathologic evaluation of implantatio! n sites demonstrated that tissue reactions in Sash mice were dramatically less compared to the reactions in normal C57BL/6 mice. Additionally, mast cells were also seen to be consistently associated with the margins of sensor tissue reactions in normal C57BL/6 mice. Finally, direct injection of bone marrow derived mast cells at sites of sensor implantation induced an acute and dramatic loss of sensor function in both C57BL/6 and Sash mice. These results demonstrate the key role of mast cells in controlling glucose sensor function in vivo. PMID: 20226521 [PubMed - as supplied by publisher] | | |
| Plasma-induced polymerization as a tool for surface functionalization of polymer scaffolds for bone tissue engineering: an in vitro study.
March 17, 2010 at 6:35 AM
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| | Plasma-induced polymerization as a tool for surface functionalization of polymer scaffolds for bone tissue engineering: an in vitro study. Acta Biomater. 2010 Mar 9; Authors: López-Pérez PM, da Silva RM, A Sousa R, Pashkuleva I, Reis RL A commonly applied strategy in tissue engineering (TE) field is the use of temporary three dimensional scaffolds for supporting and guiding tissue formation in various in vitro strategies and in vivo regeneration approaches. The interactions of these scaffolds with the highly sensitive bioentities such as living cells and tissues primary occur through the material surface. Hence, surface chemistry and topological features have the principal role in coordinating biological events at molecular, cellular and tissue levels on time scales ranging from seconds to weeks. However, tailoring the surface properties of scaffolds with complex shape and architecture remains a challenge in the materials science. Commonly applied wet chemical treatments often involve the use of toxic solvents whose oddments in the construct could be fatal in the subsequent application. Aiming to shorten the culture time in vitro (i.e. prior the implantation of the construct), in this work we pro! pose a modification of previously described bone TE scaffolds made from a blend of starch with polycaprolactone (SPCL). The modification method involves surface grafting of sulfonic or phosphonic groups via plasma-induced polymerization of vinyl sulfonic and vinyl phosphonic acid, respectively. We demonstrate herein that the presence of these anionic functional groups can modulate cell adhesion mediated through the adsorbed proteins (from the culture medium). At the studied conditions, both vitronectin adsorption and osteoblasts proliferation and viability increase in the following order SPCL<< sulfonic grafted SPCL< phosphonic grafted SPCL. The results revealed that plasma induced polymerization is an excellent alternative route, when compared to the commonly used wet chemical treatments, for the surface functionalization of biodevices with complex shape and porosity. PMID: 20226283 [PubMed - as supplied by publisher] | | |
| Construction of modular novel bioartificial liver support system.
March 17, 2010 at 6:35 AM
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| | Construction of modular novel bioartificial liver support system. Conf Proc IEEE Eng Med Biol Soc. 2009;2009:3095-8 Authors: Liu J, Song T, Jiang W, Zhang Y, Lv G, Zhao L, Zhang G, Li L A modular novel bioartificial liver support system was designed and constructed in order to simplify tedious operation of artificial liver treatment and to improve the applicability in the system. The design ideas, structure composition, system function, and etc, were described in detail. In this system, the variety of the therapy modes could be conveniently connected by the interface of modular structure. Industrial control computer was used as the main control platform, and physical of control parameters such as pressure, pump speed, dissolved oxygen, temperature, and etc, were transmitted into computer, then according to the instruction, process of the treatment was accomplished by the executing units implemented by main control system. Touch screen of human-computer interface was adopted, which made the system better operational and more comfortable. The system has passed the spot function test, and all indexes can meet requirements for the clinical treatment ! requested. It has the character such as modular design, systematic distribution, building-block structure, and etc, which supports a great novel operation platform for artificial therapy. PMID: 19963564 [PubMed - indexed for MEDLINE] | | |
| The ERK5 and ERK1/2 signaling pathways play opposing regulatory roles during chondrogenesis of adult human bone marrow-derived multipotent progenitor cells.
March 17, 2010 at 6:35 AM
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| | The ERK5 and ERK1/2 signaling pathways play opposing regulatory roles during chondrogenesis of adult human bone marrow-derived multipotent progenitor cells. J Cell Physiol. 2010 Mar 15; Authors: Bobick BE, Matsche AI, Chen FH, Tuan RS Adult human bone marrow-derived multipotent progenitor cells (MPCs) are able to differentiate into a variety of specialized cell types, including chondrocytes, and are considered a promising candidate cell source for use in cartilage tissue engineering. In this study, we examined the regulation of MPC chondrogenesis by mitogen-activated protein kinases in an attempt to better understand how to generate hyaline cartilage in the laboratory that more closely resembles native tissue. Specifically, we employed the high-density pellet culture model system to assess the roles of ERK5 and ERK1/2 pathway signaling in MPC chondrogenesis. Western blotting revealed that high levels of ERK5 phosphorylation correlate with low levels of MPC chondrogenesis and that as TGF-beta3-enhanced MPC chondrogenesis proceeds, phospho-ERK5 levels steadily decline. Conversely, levels of phospho-ERK1/2 paralleled the progression of MPC chondrogenesis. siRNA-mediated knockdown of ERK5 pathway c! omponents MEK5 and ERK5 resulted in increased MPC pellet mRNA transcript levels of the cartilage-characteristic marker genes SOX9, COL2A1, AGC, L-SOX5, and SOX6, as well as enhanced accumulation of SOX9 protein, collagen type II protein, and Alcian blue-stainable proteoglycan. In contrast, knockdown of ERK1/2 pathway members MEK1 and ERK1 decreased expression of all chondrogenic markers tested. Finally, overexpression of MEK5 and ERK5 also depressed MPC chondrogenesis, as indicated by diminished activity of a co-transfected collagen II promoter-luciferase reporter construct. In conclusion, our results suggest a novel role for the ERK5 pathway as an important negative regulator of adult human MPC chondrogenesis and illustrate that the ERK5 and ERK1/2 kinase cascades play opposing roles regulating MPC cartilage formation. J. Cell. Physiol. (c) 2010 Wiley-Liss, Inc. PMID: 20232315 [PubMed - as supplied by publisher] | | |
| Multidistrict human mesenchymal vascular cells: pluripotency and stemness characteristics.
March 17, 2010 at 6:35 AM
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| | Multidistrict human mesenchymal vascular cells: pluripotency and stemness characteristics. Cytotherapy. 2010 Mar 15; Authors: Pasquinelli G, Pacilli A, Alviano F, Foroni L, Ricci F, Valente S, Orrico C, Lanzoni G, Buzzi M, Luigi Tazzari P, Pagliaro P, Stella A, Paolo Bagnara G Abstract Background aims. The presence of ectopic tissues in the pathologic artery wall raises the issue of whether multipotent stem cells may reside in the vasculature itself. Recently mesenchymal stromal cells (MSC) have been isolated from different human vascular segments (VW MSC), belying the previous view that the vessel wall is a relatively quiescent tissue. Methods. Resident multipotent cells were recovered from fresh arterial segments (aortic arches, thoracic and femoral arteries) collected in a tissue-banking facility and used to establish an in situ and in vitro study of the stemness features and multipotency of these multidistrict MSC populations. Results. Notch-1(+), Stro-1(+), Sca-1(+) and Oct-4(+) cells were distributed along an arterial wall vasculogenic niche. Multidistrict VW MSC homogeneously expressed markers of stemness (Stro-1, Notch-1 and Oct-4) and MSC lineages (CD44, CD90, CD105, CD73, CD29 and CD166) whilst they were negative for hematopoi! etic and endothelial markers (CD34, CD45, CD31 and vWF). Each VW MSC population had characteristics of stem cells, i.e. a high efflux capability for Hoechst 33342 dye and the ability to form spheroids when grown in suspension and generate colonies when seeded at low density. Again, VW MSC cultured in induction media exhibited adipogenic, chondrogenic and leiomyogenic potential but less propensity to osteogenic differentiation, as documented by histochemical, immunohistochemical, molecular and electron microscopy analysis. Conclusions. Overall, these findings may enlighten the physiopathologic mechanisms of vascular wall diseases as well as having potential implications for cellular, genetic and tissue engineering approaches to treating vascular pathologies when these are unresponsive to medical and surgical therapies. PMID: 20230218 [PubMed - as supplied by publisher] | | |
| Sustained VEGF Delivery Via PLGA Nanoparticles Promotes Vascular Growth.
March 17, 2010 at 6:35 AM
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| | Sustained VEGF Delivery Via PLGA Nanoparticles Promotes Vascular Growth. Am J Physiol Heart Circ Physiol. 2010 Mar 12; Authors: Golub JS, Kim YT, Duvall CL, Bellamkonda RV, Gupta D, Lin AS, Weiss D, Taylor WR, Guldberg RE Technologies to increase tissue vascularity are critically important to the fields of tissue engineering and cardiovascular medicine. Currently, limited technologies exist to encourage angiogenesis and arteriogenesis in a controlled manner. We describe here an injectable controlled release system consisting of vascular endothelial growth factor (VEGF) encapsulated in poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NP). The majority of VEGF was released gradually over 2-4 days from the NPs as determined by an ELISA release kinetics study. An in vitro aortic ring bioassay was used to verify the bioactivity of VEGF-NP compared to empty NP and no treatment. A mouse femoral artery ischemia model was then used to measure revascularization in VEGF-NP treated limbs compared to limbs treated with naked VEGF and saline. 129/Sv mice were anesthetized with isoflurane and a region of the common femoral artery and vein was ligated and excised. Mice were then injected with V! EGF-NP, naked VEGF, or saline. After four days, 3D microcomputed tomography (microCT) angiography was employed to quantify vessel growth and morphology. Mice receiving VEGF-NP treatment showed a significant increase in total vessel volume and vessel connectivity compared to 5 mug VEGF, 2.5 mug VEGF, and saline treatment (all p<0.001). When taking the yield of the fabrication process into account, VEGF-NPs were over an order of magnitude more potent than naked VEGF in increasing blood vessel volume. Differences between VEGF-NP and all other groups were even greater when analyzing only small-sized vessels under 300 mum diameter. In conclusion, sustained VEGF delivery via PLGA nanoparticles shows promise for encouraging blood vessel growth in tissue engineering and cardiovascular medicine applications. Key words: tissue engineering, nanoparticle, angiogenesis, arteriogenesis. PMID: 20228260 [PubMed - as supplied by publisher] | | |
| Bioengineering of the silica-polymerizing enzyme silicatein-alpha for a targeted application to hydroxyapatite.
March 17, 2010 at 6:35 AM
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| | Bioengineering of the silica-polymerizing enzyme silicatein-alpha for a targeted application to hydroxyapatite. Acta Biomater. 2010 Mar 9; Authors: Natalio F, Link T, Müller WE, Schröder HC, Cui FZ, Wang X, Wiens M Since its discovery, numerous biotechnological approaches aim to explore the silica-polymerizing catalytic activity of the enzyme silicatein. In vivo, silicatein catalyzes polymerization of amorphous silica nanospheres from soluble precursors. In vitro, it directs the formation of nanostructured biosilica. This is of interest for various applications that strive to benefit from both the advantages of the biological system (i.e., silica synthesis under physiological conditions) and the cell mineralization-stimulating effect of biosilica. However, so far immobilization of silicatein was hampered by a complex multistep procedure. In addition, the chemical surface modifications involved not only restrict the choice of carrier materials but also render application of silicatein to hydroxyapatite (HA) of mineralized tissue impossible. Here we describe bioengineering of silicatein, adapted for application in the fields of bone regeneration, tissue engineering, and dental! care. Inspired by Glu-rich sequences of mammalian proteins that confer binding affinity to HA, a novel protein-tag was developed, the Glu-tag. Following expression of Glu-tagged silicatein the HA-binding capacity of the enzyme is demonstrated in combination with synthetic and dental HA. Furthermore, immobilized Glu-tagged silicatein catalyzes synthesis of biosilica coatings on both synthetic HA nanofibrils and dental HA. Hence, Glu-tagged silicatein reveals a considerable biomedical potential with regenerative and prophylactic implementations. PMID: 20226280 [PubMed - as supplied by publisher] | | | | 
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