| ACL prosthesis: any promise for the future?
November 17, 2009 at 9:57 am
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| | ACL prosthesis: any promise for the future? Knee Surg Sports Traumatol Arthrosc. 2009 Nov 14; Authors: Bernardino S Biological tissue autograft reconstruction using the patellar tendon or quadrupled semitendinosus/gracilis tendons has become the most popular procedure in surgical treatment of a ruptured anterior cruciate ligament (ACL). This article provides a review of the history of the use of prosthetics with respect to ACL reconstruction grafts including Carbon Fibre, Gore-Tex and Dacron prosthetics, as well as the Leeds-Keio Artificial Ligament and the Kennedy Ligament Augmentation Device (LAD). Emphasis is placed on the ligament advanced reinforcement system (LARS) as preliminary investigations of its use have been encouraging. Significant progress has been made recently with respect to the understanding of ACL anatomy, composition, biomechanics, and healing processes, leading to innovative techniques using approaches based in tissue engineering principles. Most of grafts that have been developed to date have failed due to unsatisfactory long-term physiological and functional performance. Most permanent ACL prostheses are prone to creep, fatigue, and mechanical failure within several years after implantation. In view of these factors, prosthetics are not widely used today in ACL reconstruction, and autogenous tissue grafts remain the gold standard used by the majority of surgeons. Perhaps development of resorbable, tissue inducing and cell-seeded biomaterials will improve the long-term biomechanical performance of the reconstructed ACL. Tissue ingrowth scaffolds and ligament augmentation devices require further refinement to provide effective mechanical support while avoiding stress shielding of the host tissue. While research into improved ACL treatment options continues, the synthesis of recent advancements provides some new optimism towards the regeneration of an ACL mirroring its original stability, function, and longevity. PMID: 19915821 [PubMed - as supplied by publisher] |
| Generation of induced pluripotent stem cells by reprogramming mouse embryonic fibroblasts with a four transcription factor, doxycycline inducible lentiviral transduction system.
November 17, 2009 at 9:57 am
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| | Generation of induced pluripotent stem cells by reprogramming mouse embryonic fibroblasts with a four transcription factor, doxycycline inducible lentiviral transduction system. J Vis Exp. 2009;(33): Authors: Hamilton B, Feng Q, Ye M, Welstead GG Using a defined set of transcription factors and cell culture conditions, Yamanaka and colleagues demonstrated that retrovirus-mediated delivery and expression of Oct4, Sox2, c-Myc, and Klf4 is capable of inducing pluripotency in mouse fibroblasts.(1) Subsequent reports have demonstrated the utility of the doxycycline (DOX) inducible lentiviral delivery system for the generation of both primary and secondary iPS cells from a variety of other adult mouse somatic cell types.(2,3) Induced pluripotent stem (iPS) cells are similar to embryonic stem (ES) cells in morphology, proliferation and ability to induce teratoma formation. Both types of cell can be used as the pluripotent starting material for the generation of differentiated cells or tissues in regenerative medicine.(4-6) iPS cells also have a distinct advantage over ES cells as they exhibit key properties of ES cells without the ethical dilemma of embryo destruction. Here we demonstrate the protocol for reprogramming mouse embryonic fibroblast (MEF) cells with the Stemgent DOX Inducible Mouse TF Lentivirus Set. We also demonstrate that the Stemgent DOX Inducible Mouse TF Lentivirus Set is capable of expressing each of the four transcription factors upon transduction into MEFs thereby inducing a pluripotent stem cell state that displays the pluripotency markers characteristic of ES cells. PMID: 19915522 [PubMed - in process] |
| Regenerative Medicine Special Feature: Bioengineered corporal tissue for structural and functional restoration of the penis.
November 17, 2009 at 9:57 am
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| | Regenerative Medicine Special Feature: Bioengineered corporal tissue for structural and functional restoration of the penis. Proc Natl Acad Sci U S A. 2009 Nov 13; Authors: Chen KL, Eberli D, Yoo JJ, Atala A Various reconstructive procedures have been attempted to restore a cosmetically acceptable phallus that would allow normal reproductive, sexual, and urinary function in patients requiring penile reconstruction. However, these procedures are limited by a shortage of native penile tissue. We previously demonstrated that a short segment of the penile corporal body can be replaced using naturally derived collagen matrices with autologous cells. In the current study, we examined the feasibility of engineering the entire pendular penile corporal bodies in a rabbit model. Neocorpora were engineered from cavernosal collagen matrices seeded with autologous cells using a multistep static/dynamic procedure, and these were implanted to replace the excised corpora. The bioengineered corpora demonstrated structural and functional parameters similar to native tissue and male rabbits receiving the bilateral implants were able to successfully impregnate females. This study demonstrates that neocorpora can be engineered for total pendular penile corporal body replacement. This technology has considerable potential for patients requiring penile reconstruction. PMID: 19915140 [PubMed - as supplied by publisher] |
| Re: Minja J. Pfeiffer, Jack A. Schalken. Stem Cell Characteristics in Prostate Cancer Cell Lines. Eur Urol. In press. doi:10.1016/j.eururo.2009.01.015.
November 17, 2009 at 9:57 am
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| | Re: Minja J. Pfeiffer, Jack A. Schalken. Stem Cell Characteristics in Prostate Cancer Cell Lines. Eur Urol. In press. doi:10.1016/j.eururo.2009.01.015. Eur Urol. 2009 Nov 10; Authors: Drewa T PMID: 19914771 [PubMed - as supplied by publisher] |
| O-GlcNAc Mediated Glycosylation Down-Regulation in Mice With Cyclophosphamide Induced Cystitis.
November 17, 2009 at 9:57 am
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| | O-GlcNAc Mediated Glycosylation Down-Regulation in Mice With Cyclophosphamide Induced Cystitis. J Urol. 2009 Nov 13; Authors: Chung S, Kang DO, Yamzon J, Warburton D, Koh CJ PURPOSE: Cyclophosphamide induced cystitis is an established model for the study of bladder injury and wound healing. Glycosylation is an important modification mechanism that regulates the structure and function of secreted proteins and growth factors from inflammation sites. We determined the effect of cyclophosphamide induced cystitis on O-GlcNAc mediated glycosylation in the bladder. MATERIALS AND METHODS: Cystitis in WT C57BL6 mice was induced with intraperitoneal cyclophosphamide. Retrieved bladders were analyzed using histology, immunohistochemistry, reverse transcriptase-polymerase chain reaction and Western blot for glycosylation associated factors. RESULTS: Acute bladder injury was seen up to 168 hours (7 days) after injection. Reverse transcriptase-polymerase chain reaction revealed down-regulation of O-GlcNAc transferase, a key enzyme in O-GlcNAc mediated glycosylation, at the 8, 48 and 168-hour time points. Also, the glycosidase menangioma expressed antigen 5 was up-regulated at similar time points. Western blot analysis revealed decreased glycosylated protein during cyclophosphamide induced inflammation. CONCLUSIONS: To our knowledge we report the first study of alterations in O-GlcNAc mediated glycosylation activity in bladders with cyclophosphamide induced cystitis. Glycosylation may have a significant role in the bladder wound healing process. Future studies of the glycosylation signaling pathways in the bladder would assist in future potential therapy for bladder inflammatory disease and cancer by elucidating pathways that guide bladder development and wound healing. PMID: 19914650 [PubMed - as supplied by publisher] |
| Preparation of coculture system with three extracellular matrices using capillary force lithography and layer-by-layer deposition.
November 17, 2009 at 9:57 am
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| | Preparation of coculture system with three extracellular matrices using capillary force lithography and layer-by-layer deposition. J Biosci Bioeng. 2009 Dec;108(6):544-50 Authors: Takahashi S, Yamazoe H, Sassa F, Suzuki H, Fukuda J Micropatterned cocultures were fabricated with 3 extracellular matrices, hyaluronic acid (HA), fibronectin, and collagen. The feature of the fabrication processes is to avoid the use of potentially cytotoxic materials and utilize capillary force of the solution and interactions between the extracellular matrix components. The coculture system can be used to investigate the effects of heterocellular interactions on cellular fate. Direct heterocellular connections between hepatocytes and fibroblasts were visualized by the transcellular diffusion of fluorescein in this coculture system. The interactions between hepatocytes and fibroblasts were crucial for the maintenance of albumin synthesis by hepatocytes. The coculture system was also beneficial for investigating the effects of cell-cell interactions on the induction of embryonic stem (ES) cell differentiation. In cocultures grown in a sea-island pattern, ES cells formed isolated colonies surrounded by PA6 cells and differentiated into neurons with branched neurites that extended from the colonies. This versatile and biocompatible coculture system could potentially be a powerful tool for investigating cell-cell interaction and for tissue engineering applications. PMID: 19914591 [PubMed - in process] |
| Preparation of artificial skeletal muscle tissues by a magnetic force-based tissue engineering technique.
November 17, 2009 at 9:57 am
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| | Preparation of artificial skeletal muscle tissues by a magnetic force-based tissue engineering technique. J Biosci Bioeng. 2009 Dec;108(6):538-43 Authors: Yamamoto Y, Ito A, Kato M, Kawabe Y, Shimizu K, Fujita H, Nagamori E, Kamihira M Artificial muscle tissues composed of mouse myoblast C2C12 cells were prepared using a magnetic force-based tissue engineering technique. C2C12 cells labeled with magnetite nanoparticles were seeded into the wells of 24-well ultralow-attachment culture plates. When a magnet was positioned underneath each plate, the cells accumulated evenly on the culture surface and formed multilayered cell sheets. Since the shapes of artificial tissue constructs can be controlled by magnetic force, cellular string-like assemblies were formed by using a linear magnetic field concentrator with a magnet. However, the resulting cellular sheets and strings shrank considerably and did not retain their shapes during additional culture periods for myogenic differentiation. On the other hand, when a silicone plug was positioned at the center of the well during the fabrication of a cell sheet, the cell sheet shrank drastically and formed a ring-like assembly around the plug. A histological examination revealed that the cells in the cellular ring were highly oriented in the direction of the circumference by the tension generated within the structure. Individual cellular rings were hooked around two pins separated by 10 mm, and successfully cultured for 6 d without breakage. After a 6-d culture in differentiation medium, the C2C12 cells differentiated to form myogenin-positive multinucleated myotubes. Highly dense and oriented skeletal muscle tissues were obtained using this technique, suggesting that this procedure may represent a novel strategy for muscle tissue engineering. PMID: 19914590 [PubMed - in process] |
| Bone morphogenic protein-2 (BMP-2) loaded nanoparticles mixed with human mesenchymal stem cell in fibrin hydrogel for bone tissue engineering.
November 17, 2009 at 9:57 am
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| | Bone morphogenic protein-2 (BMP-2) loaded nanoparticles mixed with human mesenchymal stem cell in fibrin hydrogel for bone tissue engineering. J Biosci Bioeng. 2009 Dec;108(6):530-7 Authors: Park KH, Kim H, Moon S, Na K Recent tissue engineering efforts have been focused on the use of natural or synthetic matrices which combine the characteristics of biodegradable properties with those of protein delivery vehicles, allowing for implanted cell actions and enhanced tissue regeneration. The principal objective of this study was to assess the feasibility of ectopic bone formation in a three-dimensional fibrin construct mixed with bone morphogenic protein-2 (BMP-2) loaded in nano-carriers for the osteogenic differentiation of human mesenchymal stem cells (hMSCs). The results of our evaluation showed that the osteogenic differentiation of hMSCs embedded in the fibrin construct was affected significantly by the stimulation of growth factors loaded in nanoparticles. When the osteoinduction activity of hMSCs in fibrin construct was evaluated in an in vitro test followed by RT-PCR, real time-QPCR, Western blotting, histological and immunohistochemical examinations, significant homogeneous bone formation was observed histologically throughout the fibrin construct containing the growth factor (BMP-2) loaded into the nanoparticles. With the above detection techniques, the BMP-2-loaded nanoparticles encapsulated in fibrin constructs evidenced more potent effects of hMSCs on bone regeneration as compared to the control or BMP-2 loaded fibrin constructs without nanoparticles. In the current study, we conclude that fibrin constructs containing BMP-2 loaded nanoparticles will be a promising method by which bone regeneration can be enhanced. PMID: 19914589 [PubMed - in process] |
| From stem cells and cadaveric matrix to engineered organs.
November 17, 2009 at 9:57 am
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| | From stem cells and cadaveric matrix to engineered organs. Curr Opin Biotechnol. 2009 Nov 12; Authors: Taylor DA The definitive treatment for end-stage heart failure, organ transplant, is limited by the supply of donor organs. Successful allograft recipients suffer significant adverse effects from chronic antirejection medications. Positive clinical treatment of injured myocardium with stem/progenitor cells has led to hope that one day autologous stem-cell-derived whole or partial donor organs can be generated. Advances in the ability to isolate (or generate) stem or progenitor cells that can give rise to beating cardiocyte-like cells and vascular components, and the advent of human iPS cell technology when combined with recent advances in the generation of perfusable complex tissue scaffolds has moved the field closer to creation of a transplantable heart. As cardiac tissue engineering matures, several other simpler cardiac tissues, such as patches for focal use and human cell test beds for drug screening and drug discovery, are emerging. PMID: 19914057 [PubMed - as supplied by publisher] |
| Thermoresponsive self-assembled elastin-based nanoparticles for delivery of BMPs.
November 17, 2009 at 9:57 am
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| | Thermoresponsive self-assembled elastin-based nanoparticles for delivery of BMPs. J Control Release. 2009 Nov 11; Authors: Bessa PC, Machado R, Nürnberger S, Dopler D, Banerjee A, Cunha AM, Rodríguez-Cabello JC, Redl H, van Griensven M, Reis RL, Casal M Elastin-like polymers are a new type of protein-based polymers that display interesting properties in the biomaterial field. Bone morphogenetic proteins (BMPs) are cytokines with a strong ability to promote new bone formation. In this work, we explored the use of elastin-like nanoparticles (average size 237.5+/-3.0nm), created by thermoresponsive self-assembly, for the combined release of bone morphogenetic protein-2 (BMP-2) and bone morphogenetic protein-14 (BMP-14). These BMPs could be encapsulated at high efficiency into the elastin-like particles and delivered in a sustained way for 14days. The activity of the growth factors was retained, as shown by the induction of ALP activity and osteogenic mineralization in C2C12 cells. Increased bioactivity was observed with a combined release of BMP-2 and BMP-14. This approach shows a significant potential for future tissue engineering applications in bone. PMID: 19913578 [PubMed - as supplied by publisher] |
| The Effects of Pulsed Inductively Coupled Plasma (PICP) on Physical Properties and Biocompatibility of Crosslinked Gelatin Films.
November 17, 2009 at 9:57 am
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| | The Effects of Pulsed Inductively Coupled Plasma (PICP) on Physical Properties and Biocompatibility of Crosslinked Gelatin Films. Int J Biol Macromol. 2009 Nov 11; Authors: Isarawut P, Rattachat M, Sorada K, Siriporn D In this work, pulsed inductively coupled plasma (PICP) device is introduced to treat crosslinked gelatin film. The effects of plasma on the properties of gelatin film were investigated. Type A gelatin film crosslinked by dehydrothermal process was treated by PICP. The properties of crosslinked gelatin were characterized by differential scanning calorimetry (DSC), amino acid content assay (TNBS), contact angle measurement and atomic force microscopy (AFM). The results showed that pulsed inductively coupled plasma did not significantly affect the thermal behavior and the degree of crosslinking of crosslinked gelatin film. The contact angle by both water and ethylene glycol of crosslinked gelatin films treated with nitrogen plasma was decreased in comparison with untreated film. The surface energy was slightly increased when increasing number of repeated discharges were applied from 1 to 20 times. This implied that nitrogen plasma could improve hydrophilicity of the crosslinked gelatin surface. The result from AFM revealed that surface roughness of crosslinked gelatin film was introduced when PICP treatment was applied. In vitro test using L929 mouse fibroblast revealed that, the number of cells proliferated on PICP-treated samples was higher than that on untreated samples. The results indicated that PICP is a potential method for crosslinked gelatin surface modification for future tissue engineering applications. PMID: 19913572 [PubMed - as supplied by publisher] |
| Novel chitin and chitosan nanofibers in biomedical applications.
November 17, 2009 at 9:57 am
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| | Novel chitin and chitosan nanofibers in biomedical applications. Biotechnol Adv. 2009 Nov 10; Authors: Jayakumar R, Prabaharan M, Nair SV, Tamura H Chitin and its deacetylated derivative, chitosan, are non-toxic, antibacterial, biodegradable and biocompatible biopolymers. Due to these properties, they are widely used for biomedical applications such as tissue engineering scaffolds, drug delivery, wound dressings, separation membranes and antibacterial coatings, stent coatings, and sensors. In the recent years, electrospinning has been found to be a novel technique to produce chitin and chitosan nanofibers. These nanofibers find novel applications in biomedical fields due to their high surface area and porosity. This article reviews the recent reports on the preparation, properties and biomedical applications of chitin and chitosan based nanofibers in detail. PMID: 19913083 [PubMed - as supplied by publisher] |
| [Induction of hepatic specification of human adipose-derived stem cells (hADSCs) in vitro.]
November 17, 2009 at 9:57 am
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| | [Induction of hepatic specification of human adipose-derived stem cells (hADSCs) in vitro.] Zhonghua Gan Zang Bing Za Zhi. 2009 Jul;17(7):544-8 Authors: Wang M, Pei HY, Guan LD, Nan X, Bai CX, Liu H, Li BW, Wang YF, Pei XT OBJECTIVE: To induce hepatic differentiation of human adipose-derived stem cells (hADSCs) in vitro. METHODS: hADSCs were isolated from human adipose tissue and treated with improved hepatic medium containing HGF, bFGF and FGF4. After 7 days of culture, OSM was added to the culture media. Cell growth during hepatic differentiation was evaluated by CCK8 assay. Morphology of differentiation was examined under light microscope. Liver specific genes and proteins were detected by RT-PCR analysis and immunohistochemical staining, respectively. And functional characteristics of hepatocytes were also examined. RESULTS: The number of hADSCs cultured in the improved hepatic media was increased significantly in comparison to hADSCs cultured in control media from 5 days to 21days (t = 6.59, 8.69, 15.94 and 24.64, respectively, P less than 0.05). The hADSCs-derived hepatocyte-like cells exhibited hepatocyte morphology, expressed hepatocyte markers, possessed hepatocyte-specific activities, such as uptake and excretion of indocyanine green, glycogen storage and albumin production. CONCLUSION: hADSCs can be induced into hepatocyte-like cells in this differentiation system. And this differentiation system promoted the growth of hADSCs. DOI: 10.3760/cma.j.issn.1007-3418.2009.07.017. PMID: 19912692 [PubMed - in process] |
| Application of mesenchymal stromal cells in urological diseases.
November 17, 2009 at 9:57 am
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| | Application of mesenchymal stromal cells in urological diseases. BJU Int. 2009 Nov 13; Authors: Montzka K, Heidenreich A The application of stem cells and their use in tissue-engineering approaches is emerging in clinical therapeutic intervention strategies. The use of adult stem cells, either autologous or allogenic, does not raise ethical concerns, in contrast to embryonic stem cells. Mesenchymal stromal cells (MSCs) can be easily obtained from bone marrow or from adipose tissue and further expanded in vitro. Due to their differentiation capacity, MSCs are very attractive for tissue engineering purposes. Furthermore, MSCs secrete a variety of mediators that have beneficial effects on the regenerating tissue. In this review we give an insight into stem cell hierarchy, define the properties of MSCs and summarize recent reports of their administration in urological diseases. PMID: 19912199 [PubMed - as supplied by publisher] |
| Efficient procurement of epithelial stem cells from human tissue specimens using a ROCK inhibitor Y-27632.
November 17, 2009 at 9:57 am
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| | Efficient procurement of epithelial stem cells from human tissue specimens using a ROCK inhibitor Y-27632. Tissue Eng Part A. 2009 Nov 15; Authors: Terunuma A, Pudi Limgala R, Park CJ, Choudhary I, Vogel JC The efficient culture of stem cells from epithelial tissues such as skin and corneas are important for both experimental studies and clinical applications of tissue engineering. We now demonstrate that treatment of human skin-derived keratinocytes with a Rho-associated protein kinase (ROCK) inhibitor Y-27632 for the initial 6 days of primary culture can increase the number of keratinocytes that possess stem cell properties to form colonies during in vitro culture of freshly isolated cells and subsequent passage (50-fold). Furthermore, we show that Y-27632 treatment can increase the total number of prostate epithelial cells derived from human prostate specimens. Therefore, the use of Y-27632 during primary cultures offers a simple and effective way to prepare a large number of epithelial stem cells from various human epithelial tissues. PMID: 19912046 [PubMed - as supplied by publisher] |
| Grafts in myringoplasty: utilizing a silk fibroin scaffold as a novel device.
November 17, 2009 at 9:57 am
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| | Grafts in myringoplasty: utilizing a silk fibroin scaffold as a novel device. Expert Rev Med Devices. 2009 Nov;6(6):653-64 Authors: Levin B, Rajkhowa R, Redmond SL, Atlas MD Chronic perforations of the eardrum or tympanic membrane represent a significant source of morbidity worldwide. Myringoplasty is the operative repair of a perforated tympanic membrane and is a procedure commonly performed by otolaryngologists. Its purpose is to close the tympanic membrane, improve hearing and limit patient susceptibility to middle ear infections. The success rates of the different surgical techniques used to perform a myringoplasty, and the optimal graft materials to achieve complete closure and restore hearing, vary significantly in the literature. A number of autologous tissues, homografts and synthetic materials are described as graft options. With the advent and development of tissue engineering in the last decade, a number of biomaterials have been studied and attempts have been made to mimic biological functions with these materials. Fibroin, a core structural protein in silk from silkworms, has been widely studied with biomedical applications in mind. Several cell types, including keratinocytes, have grown on silk biomaterials, and scaffolds manufactured from silk have successfully been used in wound healing and for tissue engineering purposes. This review focuses on the current available grafts for myringoplasty and their limitations, and examines the biomechanical properties of silk, assessing the potential benefits of a silk fibroin scaffold as a novel device for use as a graft in myringoplasty surgery. PMID: 19911876 [PubMed - in process] |
| Adult stem cells in tissue engineering.
November 17, 2009 at 9:57 am
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| | Adult stem cells in tissue engineering. Expert Rev Med Devices. 2009 Nov;6(6):621-40 Authors: Hodgkinson T, Yuan XF, Bayat A Tissue engineering is a rapidly evolving field of research that has yet to fulfil its promise in the translation and potential application of adult stem cells in clinical practice. Recently, it has become apparent that specific adult stem cells are capable of transdifferentiation. The successful application of adult stem cells is thought to be central in creating truly biomimetic tissue. Although still most widely utilized, research suggests that in the future, bone marrow-derived stem cells may no longer be considered the most suitable candidates for use in tissue engineering. Independent studies have successfully engineered a range of tissues in vitro and in vivo using hair follicle- and adipose-derived stem cells. Owing to their potency, relative abundance and noninvasive extraction, these populations may be the most promising studied to date. This review aims to discuss these candidate adult stem cell populations in an attempt to assess the most promising avenues of research. PMID: 19911874 [PubMed - in process] |
| Biocompatibility of polyhydroxyalkanoate as a potential material for ligament and tendon scaffold material.
November 17, 2009 at 9:57 am
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| | Biocompatibility of polyhydroxyalkanoate as a potential material for ligament and tendon scaffold material. J Biomed Mater Res A. 2009 Nov 12; Authors: Rathbone S, Furrer P, Lübben J, Zinn M, Cartmell S There is a strong need for new biodegradable materials that are suitable for scaffolds in tissue engineering of tendons and ligaments. In many cases, quick degradation rates are favorable, however, with respect to ligament and tendon replacement, slowly degrading polymers are clearly favored. Prime candidates are members of the large class of polyhydroxyalkanoates (PHAs), which are thermoplastic/elastomeric biopolyesters that are slowly degraded by surface erosion. Moreover, their physico-mechanical properties can be tailored during biosynthesis in bacteria or by chemical modifications. They may be spun into fibers, coated on surfaces or be part of composites. This study has investigated the biocompatability of seven different thermoplastic or elastomeric PHAs using L929 murine fibroblast cells. Cell viability and proliferation over 7 days was analyzed with live/dead staining and a picogreen assay. In addition, extracellular matrix production was measured with the hydroxyproline assay after 14 days. It was found that cell attachment to the PHA film ranged from 85-99% after 7 days. Three PHA films (PHBV (92/8), PHOUE-POSS and PHUE-O3) supported similar cell viability in comparison to the controls performed on tissue culture plastic (polystyrene), whereas the biomaterials (PHUA, PHUE, PHB and PHOUE) showed fewer viable cells than in controls. PHB, PHUE-O3, and PHBV with a water contact angle below 85 degrees supported a similar amount of collagen production in comparison to the tissue culture plastic controls. PHUA, PHUE, PHOUE, and PHOUE-POSS showed a decrease in collagen production in comparison to the controls after 14 days. Overall, PHB, PHBV, and PHUE-O3 demonstrated good performance with regards to potential use as a tissue-engineering scaffold. (c) 2009 Wiley Periodicals, Inc. J Biomed Mater Res, 2010. PMID: 19911384 [PubMed - as supplied by publisher] |
| Non-Viral Transfection of Mouse Calvarial Organ In Vitro using Accell-Modified si RNA.
November 17, 2009 at 9:57 am
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| | Non-Viral Transfection of Mouse Calvarial Organ In Vitro using Accell-Modified si RNA. Plast Reconstr Surg. 2009 Nov 11; Authors: Gupta AK, Eshraghi Y, Gliniak C, Gosain AK BACKGROUND:: Understanding the biology of cranial suture fusion and the precise role of involved molecules implicated in the process will help to identify key factors involved in regulation of suture fusion. Modulation of these key factors may serve as a tissue engineering technique to replace the traditional surgical procedures for the correction of premature suture fusion. Modulation of gene expression by RNA interference (RNAi) is a widely used technique with high potential. Since there is no available report of calvarial organ transfection in vitro, the authors studied the development of a successful non-viral delivery technique of small inhibitory RNA (siRNA) to an in vitro calvarial organ culture system. METHODS:: 19 day-old male CD1 mice were euthanized and parallel craniotomies made through the parietal and frontal calvaria, 2 mm to either side of the sagittal suture taking care to preserve the underlying dura mater. Organs grown in vitro in a defined medium were transfected with TGF-beta1-specific Accell-modified siRNA followed by RNA isolation and quantitative PCR analysis. RESULTS:: Transfection of calvarial organ with TGF-beta1 specific Accell-modified siRNA effectively knocks down the mRNA level. CONCLUSIONS:: Observations from this study indicate that in an in vitro calvarial organ culture system a specific, efficient and durable RNAi activity can be achieved when Accell-modified siRNA is used. In addition to bypassing the need for toxic lipid carriers, the modifications introduced in Accell siRNAs make it more stable and less off-target. This technique can potentially be used for in vivo studies once the initial effect of gene specific siRNA on in vitro suture fusion has been determined. PMID: 19910849 [PubMed - as supplied by publisher] |
| Prolactin induces MAPK signaling in neural progenitors without alleviating glucocorticoid-induced inhibition of in vitro neurogenesis.
November 17, 2009 at 9:57 am
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| | Prolactin induces MAPK signaling in neural progenitors without alleviating glucocorticoid-induced inhibition of in vitro neurogenesis. Cell Physiol Biochem. 2009;24(5-6):397-406 Authors: Wagner K, Couillard-Despres S, Lehner B, Brockhoff G, Rivera FJ, Blume A, Neumann I, Aigner L We recently demonstrated that prolactin (PRL) prevents chronic stress-induced inhibition of adult hippocampal neurogenesis. It remained unsettled, however, whether PRL is acting directly on neural stem and progenitors cells (NPCs) or if neurogenesis is affected by an indirect mechanism, for example through the extensively described effects of PRL on the HPA axis. To address this point, we used neurosphere cultures derived from the adult rat hippocampus as an in vitro model for NPCs. Dexamethasone (DEX) was applied to stress the NPCs, and proliferation, survival and differentiation of cells were examined. DEX markedly inhibited proliferation of NPCs and cells entered the G(0) phase of cell cycle. Moreover, DEX reduced NPC survival and repressed astroglial differentiation, which is normally induced by serum or bone morphogenetic protein application. Even though we could demonstrate that NPCs express the PRL receptor and ERK1/2 signaling is induced by PRL, we did not observe any effect of PRL on NPCs proliferation, differentiation or survival, neither in the presence nor during absence of DEX. In summary, our results indicate that PRL action on NPCs and neurogenesis in vivo occurs via an indirect mechanism. PMID: 19910680 [PubMed - in process] |
| Regulation of adipogenic differentiation by LAR tyrosine phosphatase in human mesenchymal stem cells and 3T3-L1 preadipocytes.
November 17, 2009 at 9:57 am
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| | Regulation of adipogenic differentiation by LAR tyrosine phosphatase in human mesenchymal stem cells and 3T3-L1 preadipocytes. J Cell Sci. 2009 Nov 15;122(Pt 22):4160-7 Authors: Kim WK, Jung H, Kim DH, Kim EY, Chung JW, Cho YS, Park SG, Park BC, Ko Y, Bae KH, Lee SC Mesenchymal stem cells (MSCs) are multipotent adult stem cells that can differentiate into a variety of mesodermal-lineage cells. MSCs have significant potential in tissue engineering and therapeutic applications; however, the low differentiation and proliferation efficiencies of these cells in the laboratory are fundamental obstacles to their therapeutic use, mainly owing to the lack of information on the detailed signal-transduction mechanisms of differentiation into distinct lineages. With the aid of protein-tyrosine-phosphatase profiling studies, we show that the expression of leukocyte common antigen related (LAR) tyrosine phosphatase is significantly decreased during the early adipogenic stages of MSCs. Knockdown of endogenous LAR induced a dramatic increase in adipogenic differentiation, whereas its overexpression led to decreased adipogenic differentiation in both 3T3-L1 preadipocytes and MSCs. LAR reduces tyrosine phosphorylation of the insulin receptor, in turn leading to decreased phosphorylation of the adaptor protein IRS-1 and its downstream molecule Akt (also known as PKB). We propose that LAR functions as a negative regulator of adipogenesis. Furthermore, our data support the possibility that LAR controls the balance between osteoblast and adipocyte differentiation. Overall, our findings contribute to the clarification of the mechanisms underlying LAR activity in the differentiation of MSCs and suggest that LAR is a candidate target protein for the control of stem-cell differentiation. PMID: 19910497 [PubMed - in process] |
| Autologous blood cell therapies from pluripotent stem cells.
November 17, 2009 at 9:57 am
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| | Autologous blood cell therapies from pluripotent stem cells. Blood Rev. 2009 Nov 10; Authors: Lengerke C, Daley GQ The discovery of human embryonic stem cells (hESCs) raised promises for a universal resource for cell based therapies in regenerative medicine. Recently, fast-paced progress has been made towards the generation of pluripotent stem cells (PSCs) amenable for clinical applications, culminating in reprogramming of adult somatic cells to autologous PSCs that can be indefinitely expanded in vitro. However, besides the efficient generation of bona fide, clinically safe PSCs (e.g., without the use of oncoproteins and gene transfer based on viruses inserting randomly into the genome), a major challenge in the field remains how to efficiently differentiate PSCs to specific lineages and how to select cells that will function normally upon transplantation in adults. In this review, we analyse the in vitro differentiation potential of PSCs to the hematopoietic lineage by discussing blood cell types that can be currently obtained, limitations in derivation of adult-type HSCs and prospects for clinical application of PSCs-derived blood cells. PMID: 19910091 [PubMed - as supplied by publisher] |
| Notch signalling in ischaemia-induced angiogenesis.
November 17, 2009 at 9:57 am
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| | Notch signalling in ischaemia-induced angiogenesis. Biochem Soc Trans. 2009 Dec;37(Pt 6):1221-7 Authors: Zen AA, Madeddu P Notch signalling represents a key pathway essential for normal vascular development. Recently, great attention has been focused on the implication of Notch pathway components in postnatal angiogenesis and regenerative medicine. This paper critically reviews the most recent findings supporting the role of Notch in ischaemia-induced neovascularization. Notch signalling reportedly regulates several steps of the reparative process occurring in ischaemic tissues, including sprouting angiogenesis, vessel maturation, interaction of vascular cells with recruited leucocytes and skeletal myocyte regeneration. Further characterization of Notch interaction with other signalling pathways might help identify novel targets for therapeutic angiogenesis. PMID: 19909251 [PubMed - in process] |
| Platelet-lysate As An Autologous Alternative For Fetal Bovine Serum In Cardiovascular Tissue Engineering.
November 17, 2009 at 9:57 am
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| | Platelet-lysate As An Autologous Alternative For Fetal Bovine Serum In Cardiovascular Tissue Engineering. Tissue Eng Part A. 2009 Nov 12; Authors: Riem Vis P, Bouten C, Sluijter J, Pasterkamp G, van Herwerden L, Kluin J There is an ongoing search for alternative tissue culture sera to engineer autologous tissues, since use of fetal bovine serum (FBS) is limited under Good Tissue Practice (GTP) guidelines. We compared FBS with human Platelet-lysate (PL) in media for in vitro cell culture. A threefold increase in duplication rate was found when human, saphenous vein-derived myofibroblasts were cultured in PL, while expression of marker proteins (alpha-smooth muscle actin, vimentin, desmin and non-muscle myosin heavy chain) was similar. Hsp47 mRNA-expression was increased in PL-cells and type III collagen fibers were seen on PL-cell monolayers, but not on cells cultured in FBS. These results imply a more efficient collagen fiber production. We also found higher levels of proteins involved in tissue repair and collagen remodeling, which could explain increased production of proteases and protease inhibitors by PL-cells. Our findings indicate that PL is beneficial because of the increased duplication rate, in addition to the increased matrix production and remodeling. This could lead to production of strong tissue with properly organized collagen fibers, which is important for heart valve tissue engineering. PMID: 19908968 [PubMed - as supplied by publisher] |
| Multiphoton Imaging and Quantitative Analysis of Collagen Production by Chondrogenic Human Mesenchymal Stem Cells Cultured in Chitosan Scaffold.
November 17, 2009 at 9:57 am
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| | Multiphoton Imaging and Quantitative Analysis of Collagen Production by Chondrogenic Human Mesenchymal Stem Cells Cultured in Chitosan Scaffold. Tissue Eng Part C Methods. 2009 Nov 12; Authors: Chen WL, Huang CH, Chiou LL, Chen T, Huang YY, Jiang CC, Lee HS, Dong CY We used the combined imaging modality of multiphoton autofluorescence (MAF) and second harmonic generation (SHG) microscopy to investigate the chondrogenic process of human mesenchymal stem cells (hMSCs) cultured in chitosan scaffold. Isolated hMSCs seeded onto chitosan scaffold were induced to undergo chondrogenesis by addition of the transforming growth factor TGF-beta3. Following continuous culturing, the engineered tissues at the same scaffold location were imaged at different time points for up to 49 days. Using the acquired images of the chondrogenic process, we quantify tissue morphogenesis by monitoring the changes in MAF and SHG signals from the engineered tissues. We found that the extracellular matrix (ECM) generation can be modeled by an exponential function during the initial growth stage, and that saturation occurs between Day 11 and Day 14. Furthermore, the growth rate of the ECM was found to increase toward the surface of the chitosan scaffold. Our work demonstrates the use of multiphoton microscopy for performing long term monitoring and quantification of the tissue engineering process. PMID: 19908965 [PubMed - as supplied by publisher] |
| De Novo Design of Saccharide-Peptide Hydrogels as Synthetic Scaffolds for Tailored Cell Responses.
November 17, 2009 at 9:57 am
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| | De Novo Design of Saccharide-Peptide Hydrogels as Synthetic Scaffolds for Tailored Cell Responses. J Am Chem Soc. 2009 Nov 12; Authors: Liao SW, Yu TB, Guan Z A new class of functional saccharide-peptide copolymer-based hydrogels was synthesized and investigated as synthetic extracellular matrices for regenerative medicine applications. The polymer was composed entirely of natural building blocks, namely, galactaric acid and lysine on the backbone, with tyrosine grafted onto the side chain as a handle for enzyme-catalyzed hydrogelation. The resulting hydrogels are degradable under simulated physiological conditions and exhibit minimal cytotoxicity on dermal fibroblast and PC-12 cells. As a demonstration of the versatility of the system, the mechanical properties of the gels can be independently controlled without changing the polymer chemical composition. Using an identical copolymer solution, by simply allowing different lengths of cross-linking time, a series of hydrogels was obtained with different mechanical moduli at constant chemical structure. The moduli of the resulting hydrogels varied stepwise from 1.7, 4.1, 6.9, and 12.5 kPa to allow for systematic studies on the effects of modulus on cell behavior. It was exciting to observe that a simple change in hydrogel physical properties could induce a direct phenotypic change in cell adhesion and proliferation. Depending on the substrate mechanical modulus, the cell morphology changed and proliferation rate differed by an order of magnitude for different cell lines. These data suggest our saccharide-peptide hydrogels as promising synthetic extracellular matrices for cell culture and tissue regeneration. PMID: 19908839 [PubMed - as supplied by publisher] |
| Submerged nanocontact printing (SnCP) of thiols.
November 17, 2009 at 9:57 am
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| | Submerged nanocontact printing (SnCP) of thiols. J Nanosci Nanotechnol. 2009 Nov;9(11):6478-82 Authors: Caballero D, Samitier J, Errachid A Biological patterned surfaces having sub-micron scale resolution are of great importance in many fields of life science and biomedicine. Different techniques have been proposed for surface patterning at the nanoscale. However, most of them present some limitations regarding the patterned area size or are time-consuming. Micro/nanocontact printing is the most representative soft lithography-based technique for surface patterning at the nanoscale. Unfortunately, conventional micro/nanocontact printing also suffers from problems such as diffusion and stamp collapsing that limit pattern resolution. To overcome these problems, a simple way of patterning thiols under liquid media using submerged nanocontact printing (SnCP) over large areas (approximately cm2) achieving nanosize resolution is presented. The technique is also low cost and any special equipment neither laboratory conditions are required. Nanostructured poly(dimethyl siloxane) stamps are replicated from commercially available digital video disks. SnCP is used to stamp patterns of 200 nm 1-octadecanethiol lines in liquid media, avoiding ink diffusion and stamp collapsing, over large areas on gold substrates compared with conventional procedures. Atomic force microscopy measurements reveal that the patterns have been successfully transferred with high fidelity. This is an easy, direct, effective and low cost methodology for molecule patterning immobilization which is of interest in those areas that require nanoscale structures over large areas, such as tissue engineering or biosensor applications. PMID: 19908552 [PubMed - in process] |
| Fluid flow regulates stromal cell organization and CCL21 expression in a tissue-engineered lymph node microenvironment.
November 17, 2009 at 9:57 am
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| | Fluid flow regulates stromal cell organization and CCL21 expression in a tissue-engineered lymph node microenvironment. J Immunol. 2009 Oct 1;183(7):4273-83 Authors: Tomei AA, Siegert S, Britschgi MR, Luther SA, Swartz MA In the paracortex of the lymph node (LN), T zone fibroblastic reticular cells (TRCs) orchestrate an immune response by guiding lymphocyte migration both physically, by creating three-dimensional (3D) cell networks, and chemically, by secreting the chemokines CCL19 and CCL21 that direct interactions between CCR7-expressing cells, including mature dendritic cells and naive T cells. TRCs also enwrap matrix-based conduits that transport fluid from the subcapsular sinus to high endothelial venules, and fluid flow through the draining LN rapidly increases upon tissue injury or inflammation. To determine whether fluid flow affects TRC organization or function within a 3D network, we regenerated the 3D LN T zone stromal network by culturing murine TRC clones within a macroporous polyurethane scaffold containing type I collagen and Matrigel and applying slow interstitial flow (1-23 microm/min). We show that the 3D environment and slow interstitial flow are important regulators of TRC morphology, organization, and CCL21 secretion. Without flow, CCL21 expression could not be detected. Furthermore, when flow through the LN was blocked in mice in vivo, CCL21 gene expression was down-regulated within 2 h. These results highlight the importance of lymph flow as a homeostatic regulator of constitutive TRC activity and introduce the concept that increased lymph flow may act as an early inflammatory cue to enhance CCL21 expression by TRCs, thereby ensuring efficient immune cell trafficking, lymph sampling, and immune response induction. PMID: 19734211 [PubMed - indexed for MEDLINE] |
| Oxygen-mediated enhancement of primary hepatocyte metabolism, functional polarization, gene expression, and drug clearance.
November 17, 2009 at 9:57 am
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| | Oxygen-mediated enhancement of primary hepatocyte metabolism, functional polarization, gene expression, and drug clearance. Proc Natl Acad Sci U S A. 2009 Sep 15;106(37):15714-9 Authors: Kidambi S, Yarmush RS, Novik E, Chao P, Yarmush ML, Nahmias Y The liver is a major site for the metabolism of xenobiotic compounds due to its abundant level of phase I/II metabolic enzymes. With the cost of drug development escalating to over $400 million/drug there is an urgent need for the development of rigorous models of hepatic metabolism for preclinical screening of drug clearance and hepatotoxicity. Here, we present a microenvironment in which primary human and rat hepatocytes maintain a high level of metabolic competence without a long adaptation period. We demonstrate that co-cultures of hepatocytes and endothelial cells in serum-free media seeded under 95% oxygen maintain functional apical and basal polarity, high levels of cytochrome P450 activity, and gene expression profiles on par with freshly isolated hepatocytes. These oxygenated co-cultures demonstrate a remarkable ability to predict in vivo drug clearance rates of both rapid and slow clearing drugs with an R(2) of 0.92. Moreover, as the metabolic function of oxygenated co-cultures stabilizes overnight, preclinical testing can be carried out days or even weeks before other culture methods, significantly reducing associated labor and cost. These results are readily extendable to other culture configurations including three-dimensional culture, bioreactor studies, as well as microfabricated co-cultures. PMID: 19720996 [PubMed - indexed for MEDLINE] |
| Advances in progenitor cell therapy using scaffolding constructs for central nervous system injury.
November 17, 2009 at 9:57 am
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| | Advances in progenitor cell therapy using scaffolding constructs for central nervous system injury. Stem Cell Rev Rep. 2009 Sep;5(3):283-300 Authors: Walker PA, Aroom KR, Jimenez F, Shah SK, Harting MT, Gill BS, Cox CS Traumatic brain injury (TBI) is a major cause of morbidity and mortality in the United States. Current clinical therapy is focused on optimization of the acute/subacute intracerebral milieu, minimizing continued cell death, and subsequent intense rehabilitation to ameliorate the prolonged physical, cognitive, and psychosocial deficits that result from TBI. Adult progenitor (stem) cell therapies have shown promise in pre-clinical studies and remain a focus of intense scientific investigation. One of the fundamental challenges to successful translation of the large body of pre-clinical work is the delivery of progenitor cells to the target location/organ. Classically used vehicles such as intravenous and intra arterial infusion have shown low engraftment rates and risk of distal emboli. Novel delivery methods such as nanofiber scaffold implantation could provide the structural and nutritive support required for progenitor cell proliferation, engraftment, and differentiation. The focus of this review is to explore the current state of the art as it relates to current and novel progenitor cell delivery methods. PMID: 19644777 [PubMed - indexed for MEDLINE] |
| Development of the neuromuscular system during asexual propagation in an invertebrate chordate.
November 17, 2009 at 9:57 am
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| | Development of the neuromuscular system during asexual propagation in an invertebrate chordate. Dev Dyn. 2009 Aug;238(8):2081-94 Authors: Tiozzo S, Murray M, Degnan BM, De Tomaso AW, Croll RP Botryllus schlosseri is a colonial ascidian, and the closest relative to vertebrates that can completely regenerate its entire body, including all somatic and germline tissues, using an asexual developmental pathway called blastogenesis. This regenerative potential exhibited by Botryllus and other colonial ascidians does not exist in any other chordate and makes B. schlosseri a promising model to investigate the cellular and molecular basis of regeneration. In this report, we describe postembryonic myogenesis and characterized the development of the neural system during blastogenic development. alpha-Tubulin immunoreactivity revealed a high correlation with previous studies on the motor nervous system. The pattern of the serotoninergic system in the adult reflects that observed in solitary ascidians, but in early blastogenesis suggests a morphogenic role of this monoamine. In summary, this study provides the morphological framework to dissect the mechanisms underlying the ability to regenerate entire organ systems as an adult in a chordate model. PMID: 19618474 [PubMed - indexed for MEDLINE] |
| Private cord blood banking: current use and clinical future.
November 17, 2009 at 9:57 am
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| | Private cord blood banking: current use and clinical future. Stem Cell Rev Rep. 2009 Sep;5(3):195-203 Authors: Hollands P, McCauley C International private umbilical cord blood banking has expanded rapidly in recent years since the first cord blood transplant which was 20 years ago. Private companies offer parents the opportunity to store umbilical cord blood for the possible future use by their child or other family members. The private cord blood industry has been criticised by a number of professional bodies including the EU Ethics Committee, the Royal College of Obstetrics and Gynaecology, the Royal College of Midwives and the US College of Paediatrics. This review presents the arguments from the opponents of private cord blood banking, and then makes the case for private cord banking based on the latest scientific and clinical evidence. PMID: 19603288 [PubMed - indexed for MEDLINE] |
| Disease-dependent reciprocal phosphorylation of serine and tyrosine residues of c-Met/HGF receptor contributes disease retardation of a transgenic mouse model of ALS.
November 17, 2009 at 9:57 am
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| | Disease-dependent reciprocal phosphorylation of serine and tyrosine residues of c-Met/HGF receptor contributes disease retardation of a transgenic mouse model of ALS. Neurosci Res. 2009 Oct;65(2):194-200 Authors: Kadoyama K, Funakoshi H, Ohya-Shimada W, Nakamura T, Matsumoto K, Matsuyama S, Nakamura T Amyotrophic lateral sclerosis (ALS) is a fatal disease characterized by progressive degeneration of motoneurons. We have demonstrated that hepatocyte growth factor (HGF) attenuates loss of both spinal and brainstem motoneurons of ALS model mice expressing mutated human SOD1(G93A) (G93A). This study was designed to assess disease-dependent regulatory mechanisms of c-Met/HGF receptor (c-Met) activation in the facial motoneurons of G93A mice. Using double transgenic mice expressing HGF and mutated SOD1(G93A) (G93A/HGF), we showed that phosphorylation of c-Met tyrosine residues at positions 1230, 1234 and 1235 (phospho-Tyr), and thereby its activation, was slightly evident in G93A and highly obvious in G93A/HGF mice (but absent in WT and HGF-Tg mice). Phosphorylation of the c-Met serine residue at position 985 (phospho-Ser), a residue involved in the negative regulation of its activation, was evident in WT and HGF-Tg mice. Protein phosphatase 2A (PP2A), which is capable of dephosphorylating c-Met phospho-serine, is upregulated in the facial motoneurons of G93A and G93A/HGF mice compared with WT and HGF-Tg mice. Thus, c-Met activation is reciprocally regulated by phosphorylation between c-Met serine and tyrosine residues through PP2A induction in the presence or absence of mutant SOD1 expression, and HGF functions more efficiently in ALS and ALS-related diseases. PMID: 19595710 [PubMed - indexed for MEDLINE] |
| Rho1 has multiple functions in Drosophila wing planar polarity.
November 17, 2009 at 9:57 am
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| | Rho1 has multiple functions in Drosophila wing planar polarity. Dev Biol. 2009 Sep 1;333(1):186-99 Authors: Yan J, Lu Q, Fang X, Adler PN The frizzled (fz) signaling/signal transduction pathway controls planar cell polarity in both vertebrates and invertebrates. Previous data implicated Rho1 as a component of the fz pathway in Drosophila but it was unclear how it functioned. The existence of a G Protein Binding-Formin Homology 3 (GBD-FH3) domain in Multiple Wing Hairs, a downstream component of the pathway suggested that Rho1 might function by binding to and activating Mwh. We re-examined the role of Rho1 in wing planar polarity and found that it had multiple functions. Aberrant Rho1 activity led to changes in the number of hairs formed, changes in cell shape and F-actin and changes in cellular junctions. Experiments that utilized Rho effector loop mutations argued that these phenotypes were mediated by effects of Rho1 on the cytoskeleton and not by effects on transcription. We found strong positive genetic interactions between Rho1 and mwh, that Rho1 regulated the accumulation of Mwh protein and that these two proteins could be co-immunoprecipitated. The Mwh GBD:FH3 domain was sufficient for co-immunoprecipitation with Rho1, consistent with this domain mediating the interaction. However, further experiments showed that Rho1 function in wing differentiation was not limited to interacting with Mwh. We established by genetic experiments that Rho1 could influence hair morphogenesis in the absence of mwh and that the disruption of Rho1 activity could interfere with the zig zag accumulation pattern of upstream fz pathway proteins. Thus, our results argue that in addition to its interaction with Mwh Rho1 has functions in wing planar polarity that are parallel to and upstream of fz. The upstream function may be an indirect one and associated with the requirement for normal apical basal polarity and adherens junctions for the accumulation of PCP protein complexes. PMID: 19576201 [PubMed - indexed for MEDLINE] |
| Dynamic oxygen enhances oocyte maturation in long-term follicle culture.
November 17, 2009 at 9:57 am
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| | Dynamic oxygen enhances oocyte maturation in long-term follicle culture. Tissue Eng Part C Methods. 2009 Sep;15(3):323-32 Authors: Heise MK, Koepsel R, McGee EA, Russell AJ Traditionally, follicles have been grown in standard incubators with atmospheric oxygen concentration. However, preantral follicles exist in the avascular cortex of the ovary. This study examines the effectiveness of an oxygen delivery protocol that more closely mimics the in vivo environment of the ovary on oocyte viability, maturation, parthenogenetic activation, and fertilization from in vitro cultured rat preantral follicles. Of 54 oocytes cultured in the dynamic oxygen environment, 35 were viable while only 22 of 50 oocytes cultured within an ambient oxygen concentration remained viable (p < 0.05). Germinal vesicle breakdown was observed in 56% of oocytes from the dynamic oxygen group compared to 30% of oocytes from the ambient oxygen group (p < 0.05). Parthenogenetic activation was observed in a significant number of oocytes from the dynamic oxygen group, while none of the oocytes from the ambient oxygen group activated (p < 0.05). However, the proportions of oocytes from the dynamic oxygen group that remained viable underwent germinal vesicle breakdown, and activated were still significantly less than those from the in vivo control group (p < 0.05). Fertilization of the oocytes from the dynamic oxygen group was confirmed through a successful trial of intracytoplasmic sperm injection. PMID: 19552585 [PubMed - indexed for MEDLINE] |
| Multicenter randomized trial of robot-assisted rehabilitation for chronic stroke: methods and entry characteristics for VA ROBOTICS.
November 17, 2009 at 9:57 am
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| | Multicenter randomized trial of robot-assisted rehabilitation for chronic stroke: methods and entry characteristics for VA ROBOTICS. Neurorehabil Neural Repair. 2009 Oct;23(8):775-83 Authors: Lo AC, Guarino P, Krebs HI, Volpe BT, Bever CT, Duncan PW, Ringer RJ, Wagner TH, Richards LG, Bravata DM, Haselkorn JK, Wittenberg GF, Federman DG, Corn BH, Maffucci AD, Peduzzi P BACKGROUND: Chronic upper extremity impairment due to stroke has significant medical, psychosocial, and financial consequences, but few studies have examined the effectiveness of rehabilitation therapy during the chronic stroke period. OBJECTIVE: . To test the safety and efficacy of the MIT-Manus robotic device for chronic upper extremity impairment following stroke. METHODS: . The VA Cooperative Studies Program initiated a multicenter, randomized, controlled trial in November 2006 (VA ROBOTICS). Participants with upper extremity impairment >/=6 months poststroke were randomized to robot-assisted therapy (RT), intensive comparison therapy (ICT), or usual care (UC). RT and ICT consisted of three 1-hour treatment sessions per week for 12 weeks. The primary outcome was change in the Fugl-Meyer Assessment upper extremity motor function score at 12 weeks relative to baseline. Secondary outcomes included the Wolf Motor Function Test and the Stroke Impact Scale. RESULTS: . A total of 127 participants were randomized: 49 to RT, 50 to ICT, and 28 to UC. The majority of participants were male (96%), with a mean age of 65 years. The primary stroke type was ischemic (85%), and 58% of strokes occurred in the anterior circulation. Twenty percent of the participants reported a stroke in addition to their index stroke. The average time from the index stroke to enrollment was 56 months (range, 6 months to 24 years). The mean Fugl-Meyer score at entry was 18.9. CONCLUSIONS: . VA ROBOTICS demonstrates the feasibility of conducting multicenter clinical trials to rigorously test new rehabilitative devices before their introduction to clinical practice. The results are expected in early 2010. PMID: 19541917 [PubMed - indexed for MEDLINE] |
| Current role of resurfacing lasers.
November 17, 2009 at 9:57 am
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| | Current role of resurfacing lasers. G Ital Dermatol Venereol. 2009 Jun;144(3):229-41 Authors: Hantash BM, Gladstone HB Resurfacing lasers have been the treatment of choice for diminishing rhytids and tightening skin. The carbon dioxide and erbium lasers have been the gold and silver standards. Despite their effectiveness, these resurfacing lasers have a very high risk profile including scarring, hyperpigmentation and hypopigmentation. Because of these side effects, various practitioners have tried alternative settings for these lasers as well as alternative wavelengths, particularly in the infrared spectrum. These devices have had less downtime, but their effectiveness has been limited to fine wrinkles. As with selective photothemolysis, a major advance in the field has been fractionated resurfacing which incorporates grids of microthermal zones that spares islands of skin. This concept permits less tissue damage and quicker tissue regeneration. Initially, fractionated resurfacing was limited to the nonablative mid-infrared spectrum. These resurfacing lasers is appropriate for those patients with acne scars, uneven skin tone, mild to moderate photodamage, and is somewhat effective for melasma. Importantly, because there is less overall tissue damage and stimulation of melanocytes, these lasers can be used in darker skin types. Downtime is 2-4 days of erythema and scaling. Yet, these nonablative fractionated devices required 5-6 treatments to achieve a moderate effect. Logically, the fractionated resurfacing has now been applied to the CO2 and the Erbium:Yag lasers. These devices can treat deeper wrinkles and tighten skin. Downtime appears to be 5-7 days. The long term effectiveness and the question of whether these fractionated devices will approach the efficacy of the standard resurfacing lasers is still in question. Ultimately either integrated devices which may use fractionated resurfacing, radiofrequency and a sensitizer, or combining different lasers in a single treatment may prove to be the most effective in reducing rhtyides, smoothing the skin topography and tightening the skin envelope. PMID: 19528905 [PubMed - indexed for MEDLINE] |
| In vitro interaction between mouse breast cancer cells and mouse mesenchymal stem cells during adipocyte differentiation.
November 17, 2009 at 9:57 am
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| | In vitro interaction between mouse breast cancer cells and mouse mesenchymal stem cells during adipocyte differentiation. J Tissue Eng Regen Med. 2009 Jul;3(5):338-47 Authors: Xu F, Gomillion C, Maxson S, Burg KJ Surgical treatment following breast cancer, i.e. lumpectomy and mastectomy, may not efficiently remove all cancerous cells. As such, when mesenchymal stem cells (MSCs) are incorporated into the breast reconstruction process, it is likely that those MSCs will encounter remnant cancerous cells after transplantation into the defect site. The potential interaction between breast cancer cells and MSCs remains unclear. We hypothesized that paracrine interactions might occur between cells and various proteinases, growth factors and other cytokine molecules in the local microenvironment. Conditioned media (CM) from two mouse mammary cancer cell lines (4T1 and 4T07) and one mouse mammary epithelial cell line (NMuMG) were studied in the experimental model. Post-confluent mouse MSCs (D1 cells) were differentiated with an adipogenic hormonal cocktail. Conditioned media from the three cell types did not have an inhibitory effect on D1 cell viability; however, triglyceride (TG) and Oil red O (ORO) analysis results showed that 4T1-CM significantly inhibited D1 adipocyte differentiation and reduced lipid vesicle accumulation in the differentiating D1 cells. Preliminary analysis of the conditioned media revealed that a higher presence of matrix metalloprotease-9 (MMP-9) and urokinase plasminogen activator (uPA) was present in the 4T1-CM as compared to the levels found in 4T07-CM and NMuMG-CM, which were below the detection limit. Additionally, the conditioned medium of differentiated D1 cells on day 12 had a negative effect on 4T1 and 4T07 cell viability but no effect on NMuMG cell viability. The results suggest that mouse breast cancer cells modulate mouse MSC adipogenic differentiation, the level of modulation specific to the metastatic level. PMID: 19484721 [PubMed - indexed for MEDLINE] |
| Human cardiac mesoangioblasts isolated from hypertrophic cardiomyopathies are greatly reduced in proliferation and differentiation potency.
November 17, 2009 at 9:57 am
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| | Human cardiac mesoangioblasts isolated from hypertrophic cardiomyopathies are greatly reduced in proliferation and differentiation potency. Cardiovasc Res. 2009 Sep 1;83(4):707-16 Authors: Gálvez BG, Covarello D, Tolorenzi R, Brunelli S, Dellavalle A, Crippa S, Mohammed SA, Scialla L, Cuccovillo I, Molla F, Staszewsky L, Maisano F, Sampaolesi M, Latini R, Cossu G AIMS: Our objective was to test whether progenitor cell proliferation and differentiation potential may vary depending upon the disease of the donor. METHODS AND RESULTS: Human cardiac mesoangioblasts were isolated from cardiac muscle biopsies of patients undergoing open heart surgery for correction of mitral regurgitation following an acute myocardial infarction (MR-MI) or correction of mitral and aortic regurgitation with ensuing left ventricular hypertrophy (MAR-LVH). The cells express surface markers and cardiac genes similar to mouse cardiac mesoangioblasts; they have limited self-renewing and clonogenic activity and are committed mainly to cardiogenesis. Although cardiac differentiation can be induced by 5-azacytidine or by co-culture with rat neonatal cardiomyocytes, human cells do not contract spontaneously like their mouse counterparts. When locally injected in the infarcted myocardium of immunodeficient mice, cardiac mesoangioblasts generate a chimeric heart that contains human myocytes and some capillaries; likewise, they colonize chick embryo hearts when transplanted in ovo. At variance with cells from patients with MR-MI, when isolation was performed on biopsies from MAR-LVH, cells could be isolated in much lower numbers, proliferated less extensively and failed to differentiate. CONCLUSION: Cardiac mesoangioblasts are present in the human heart but this endogenous progenitor population is progressively exhausted, possibly by continuous and inefficient regeneration attempts. PMID: 19457891 [PubMed - indexed for MEDLINE] |
| Multiphasic collagen fibre-PLA composites seeded with human mesenchymal stem cells for osteochondral defect repair: an in vitro study.
November 17, 2009 at 9:57 am
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| | Multiphasic collagen fibre-PLA composites seeded with human mesenchymal stem cells for osteochondral defect repair: an in vitro study. J Tissue Eng Regen Med. 2009 Jul;3(5):389-97 Authors: Heymer A, Bradica G, Eulert J, Nöth U A promising approach for the repair of osteochondral defects is the use of a scaffold with a well-defined cartilage-bone interface. In this study, we used a multiphasic composite scaffold with an upper collagen I fibre layer for articular cartilage repair, separated by a hydrophobic interface from a lower polylactic acid (PLA) part for bone repair. Focusing initially on the engineering of cartilage, the upper layer was seeded with human mesenchymal stem cells (hMSCs) suspended in a collagen I hydrogel for homogeneous cell distribution. The constructs were cultured in a defined chondrogenic differentiation medium supplemented with 10 ng/ml transforming growth factor-beta1 (TGFbeta1) or in DMEM with 10% fetal bovine serum as a control. After 3 weeks a slight contraction of the collagen I fibre layer was seen in the TGFbeta1-treated group. Furthermore, a homogeneous cell distribution and chondrogenic differentiation was achieved in the upper third of the collagen I fibre layer. In the TGFbeta1-treated group cells showed a chondrocyte-like appearance and were surrounded by a proteoglycan and collagen type II-rich extracellular matrix. Also, a high deposition of glycosaminoglycans could be measured in this group and RT-PCR analyses confirmed the induction of chondrogenesis, with the expression of cartilage-specific marker genes, such as aggrecan and collagen types II and X. This multiphasic composite scaffold with the cartilage layer on top might be a promising construct for the repair of osteochondral defects. PMID: 19434664 [PubMed - indexed for MEDLINE] |
| Denuded human amniotic membrane seeding bone marrow stromal cells as an effective composite matrix stimulates axonal outgrowth of rat neural cortical cells in vitro.
November 17, 2009 at 9:57 am
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| | Denuded human amniotic membrane seeding bone marrow stromal cells as an effective composite matrix stimulates axonal outgrowth of rat neural cortical cells in vitro. Acta Neurochir (Wien). 2009 Sep;151(9):1113-20 Authors: Liang HS, Liang P, Xu Y, Wu JN, Liang T, Xu XP, Liu EZ BACKGROUND: Previous studies have shown that axonal outgrowth in the damaged central nervous system is closely related to the local microenvironment. Transplantation of bone marrow stromal cells (BMSC) or BMSC with some biomaterials has been used to treat various central nervous system diseases with some success. In the current study, we investigated if BMSC on denuded human amniotic membrane (DhAM) as a composite matrix could stimulate axonal outgrowth or not. METHOD: After completely removing the cells on the amniotic membrane with a tryptic and mechanical approach, we seeded BMSC on it. The MTS was applied to test the cytotoxicity of DhAM compared with PLGA and PLL. The morphology of the BMSC was observed by light, electronic and laser confocal microscopy. We also used four kinds of substance (PLL, DhAM, BMSC + PLL, BMSC + DhAM) to coculturing with the cortical neurons. Finally, the lengths of axons in each group were studied using the positive axon-specific marker NF-H. FINDINGS: The DhAM was devoid of cellular components and only its intact basement membrane was left. BMSC grew on the substrate and proliferated with a flat to fusiform morphology. In the MTS test, the results indicated that BMSC cultured in DhAM extract had a high survival rate (> 80%). Moreover, the cortical neural axons in the experimental group (BMSC + DhAM) were longer (287.37 +/- 12.72 microm) than in the other groups (P < 0.01). CONCLUSIONS: This study demonstrates that the DhAM was a good carrier to support growth of BMSC and BMSC on DhAM was an effective composite matrix to support the outgrowth of the axons of rat cortical neurons in vitro. Future studies of the use of the composite matrix in disorders are planned. PMID: 19404575 [PubMed - indexed for MEDLINE] |
| Organization of extracellular matrix fibers within polyglycolic acid-polylactic acid scaffolds analyzed using X-ray synchrotron-radiation phase-contrast micro computed tomography.
November 17, 2009 at 9:57 am
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| | Organization of extracellular matrix fibers within polyglycolic acid-polylactic acid scaffolds analyzed using X-ray synchrotron-radiation phase-contrast micro computed tomography. Tissue Eng Part C Methods. 2009 Sep;15(3):403-11 Authors: Albertini G, Giuliani A, Komlev V, Moroncini F, Pugnaloni A, Pennesi G, Belicchi M, Rubini C, Rustichelli F, Tasso R, Torrente Y Spatiotemporal organized patterns of cell surface-associated and extracellular matrix (ECM)-embedded molecules play important roles in the development and functioning of tissues. ECM proteins interact with the surface of bioscaffold polymers and influence material-driven control of cell differentiation., Using X-ray phase-contrast micro computed tomography (microCT), we visualized the three-dimensional (3D) image of ECM organization after in vitro seeding of bone marrow-derived human and murine mesenchymal stem cells (MSCs) induced to myogenic differentiation, labelled with iron oxide nanoparticles, and seeded onto polyglycolic acid-polylactic acid scaffolds. X-ray microCT enabled us to detect with high spatial resolution the 3D structural organization of ECM within the bioscaffold and how the presence of cells modified the construct arrangement. Species-specific differences between the matrix produced by human and murine cells were observed. In conclusion, X-ray synchrotron radiation microCT analysis appeared to be a useful tool to identify the spatiotemporal pattern of organization of ECM fibers within a bioscaffold. PMID: 19326965 [PubMed - indexed for MEDLINE] |
| Development of three-dimensional tissue-engineered models of bacterial infected human skin wounds.
November 17, 2009 at 9:57 am
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| | Development of three-dimensional tissue-engineered models of bacterial infected human skin wounds. Tissue Eng Part C Methods. 2009 Sep;15(3):475-84 Authors: Shepherd J, Douglas I, Rimmer S, Swanson L, MacNeil S While infected skin wounds are on the increase because of ageing populations, rising incidence of diabetes, and antibiotic resistance, we lack relevant in vivo or in vitro models to study many aspects of bacterial interaction with skin. The aim of this study was to develop three-dimensional models of normal human skin to study bacterial infection. The common dermatological pathogens Staphylococcus aureus and Pseudomonas aeruginosa were used to infect tissue-engineered skin, and the course of infection in the skin was examined over several days. Two forms of model were developed-one in which bacteria were introduced directly to 10 mm wounds in the epidermis, and another in which wounds were created by burning a 4 mm hole in the center of the tissue before inoculation. The bacteria flourished within the engineered skin, and colonized the upper epidermal layers before invasion into the dermis. Infection with P. aeruginosa caused a loss of epidermis and de-keratinization of the skin constructs, as well as partial loss of basement membrane. These novel complex human skin infection models could be used to investigate microbial invasion of normal skin epithelium, basement membrane, and connective tissue, and as a model to study approaches to reduce bacterial burden in skin wounds. PMID: 19292658 [PubMed - indexed for MEDLINE] |
| Microporous poly(L-lactic acid) membranes fabricated by polyethylene glycol solvent-cast/particulate leaching technique.
November 17, 2009 at 9:57 am
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| | Microporous poly(L-lactic acid) membranes fabricated by polyethylene glycol solvent-cast/particulate leaching technique. Tissue Eng Part C Methods. 2009 Sep;15(3):463-74 Authors: Selvam S, Chang WV, Nakamura T, Samant DM, Thomas PB, Trousdale MD, Mircheff AK, Schechter JE, Yiu SC With the eventual goal of developing a tissue-engineered tear secretory system, we found that primary lacrimal gland acinar cells grown on solid poly(L-lactic acid) (PLLA) supports expressed the best histiotypic morphology. However, to be able to perform vectorial transport functions, epithelia must be supported by a permeable substratum. In the present study, we describe the use of a solvent-cast/particulate leaching technique to fabricate microporous PLLA membranes (mpPLLAm) from PLLA/polyethylene glycol blends. Scanning electron microscopy revealed pores on both the air-cured ( approximately 4 microm) and glass-cured sides (<2 microm) of the mpPLLAm. Diffusion studies were performed with mpPLLAm fabricated from 57.1% PLLA/42.9% polyethylene glycol blends to confirm the presence of channelized pores. The data reveal that glucose, L-tryptophan, and dextran (a high molecular weight glucose polymer) readily permeate mpPLLAm. Diffusion of the immunoglobulin G through the mpPLLAm decreased with time, suggesting the possible adsorption and occlusion of the pores. Cells cultured on the mpPLLAm (57.1/42.9 wt%) grew to subconfluent monolayers but retained histiotypic morphological and physiological characteristics of lacrimal acinar cells in vivo. Our results suggest that mpPLLAm fabricated using this technique may be useful as a scaffold for a bioartificial lacrimal gland device. PMID: 19260769 [PubMed - indexed for MEDLINE] |
| Development of new nerve guide tube for repair of long nerve defects.
November 17, 2009 at 9:57 am
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| | Development of new nerve guide tube for repair of long nerve defects. Tissue Eng Part C Methods. 2009 Sep;15(3):387-402 Authors: Ichihara S, Inada Y, Nakada A, Endo K, Azuma T, Nakai R, Tsutsumi S, Kurosawa H, Nakamura T A novel nerve guide tube (poly (L-lactic) acid (PLLA)/ polyglycolic acid (PGA)-c-tube) capable of repairing long peripheral nerve injuries in a canine model has been developed. The tube was created by braiding together PLLA and PGA and then coating it with collagen. PLLA was newly added to the formulation to achieve higher sustainability. The tube was compared with a PGA-collagen tube in clinical use since 2002 having the same structure with a collagen coating but composed of PGA alone (PGA-c-tube). When tested for repair of a 40-mm gap in the left peroneal nerve, using PLLA/PGA-c-tube (n = 15), PGA-c-tube (n = 15), and a negative control group where the cut stump was capped using a silicone cap (n = 15), the lumen structure essential for securing the space for nerve regeneration was maintained in PLLA/PGA-c-tube for over 12 months with a higher number of axons both within the tube and at the distal nerve end. Electrophysiological evaluation revealed that the amplitude of compound muscle action potentials and sensory nerve action potentials after nerve regeneration with PLLA/PGA-c-tube were significantly higher. When assessed using magnetic resonance imaging (MRI), the volume of the tibialis anterior (TA) muscle in dogs that had undergone nerve repair using PLLA/PGA-c-tube was approximately 80% that of the positive control at 12 months. Functional analysis conducted by assessing the ankle angle revealed faster recovery in the PLLA/PGA-c-tube group. Better regeneration was achieved using a PLLA/PGA-c-tube that contains the slowly decomposing fiber material, PLLA. This indicates potential for repair of even longer nerve gaps or defects located near joints, and also clinical application. PMID: 19226199 [PubMed - indexed for MEDLINE] |
| Preservation of porcine hepatocytes in three-dimensional bioreactor at room temperature using epigallocatechin-3-gallate.
November 17, 2009 at 9:57 am
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| | Preservation of porcine hepatocytes in three-dimensional bioreactor at room temperature using epigallocatechin-3-gallate. Tissue Eng Part C Methods. 2009 Sep;15(3):345-53 Authors: Miskon A, Yamaoka T, Hyon SH, Kodama M, Uyama H A bioartificial liver (BAL) assist system employing a three-dimensional (3D) bioreactor has been studied as a temporary support in liver failure. In the present study, a novel preservation method of primary cultured porcine hepatocytes in monolayer and 3D culture systems was studied. Epigallocatechin-3-gallate (EGCG), which has recently been found to have various bioactivities, was selected as a key compound for hepatocyte preservation. Hepatocytes isolated from porcine liver using the collagenase perfusion method were pre-cultured for 6 days, preserved at room temperature in the presence of EGCG at various concentrations for 4 days, and post-cultured in normal medium for another 6 days. In the monolayer culture, only albumin production rate was fully recovered after preservation when EGCG concentration was high (0.25mg/mL). In contrast, albumin production and ammonium metabolism in the 3D bioreactor under the same condition recovered to 72+/-16% and 98+/-32%, respectively, of levels before preservation. These results indicate that hepatocytes can be preserved in the presence of 0.25mg/mL of EGCG at room temperature, especially in a 3D culture system, which is promising technology for BAL preparation. PMID: 19196126 [PubMed - indexed for MEDLINE] |
| Fabrication of nonwoven coaxial fiber meshes by electrospinning.
November 17, 2009 at 9:57 am
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| | Fabrication of nonwoven coaxial fiber meshes by electrospinning. Tissue Eng Part C Methods. 2009 Sep;15(3):333-344 Authors: Saraf A, Lozier G, Haesslein A, Kasper FK, Raphael RM, Baggett LS, Mikos AG There is a great need for biodegradable polymer scaffolds that can regulate the delivery of bioactive factors such as drugs, plasmids, and proteins. Coaxial electrospinning is a novel technique that is currently being explored to create such polymer scaffolds by embedding within them aqueous-based biological molecules. In this study, we evaluated the influence of various processing parameters such as sheath polymer concentration, core polymer concentration and molecular weight, and salt ions within the core polymer on coaxial fiber morphology. The sheath polymer used in this study was poly(e-caprolactone) (PCL), and the core polymer was poly(ethylene glycol) (PEG). We examined the effects of the various processing parameters on core diameters, total fiber diameters, and sheath thicknesses of coaxial microfibers using a 2(4) full factorial statistical model. The maximum increase in total fiber diameter was observed with increase in sheath polymer (PCL) concentration from 9 to 11 wt% (0.49+/-0.03 microm) and salt concentration within the core from 0 to 500 mM (0.38+/-0.03 microm). The core fiber diameter was most influenced by the sheath and core polymer (PCL and PEG, respectively) concentrations, the latter of which increased from 200 to 400 mg/mL (0.40+/-0.01 microm and 0.36+/-0.01 microm, respectively). The core polymer (PEG) concentration had a maximal negative effect on sheath thickness (0.40+/-0.03 microm), while salt concentration had the maximal positive effect (0.28+/-0.03 microm). Molecular weight increases in core polymer (PEG) from 1.0 to 4.6 kDa caused moderate increases in total and sheath fiber diameters and sheath thicknesses. These experiments provide important information that lays the foundation required for the synthesis of coaxial fibers with tunable dimensions. PMID: 19196125 [PubMed - indexed for MEDLINE] |
| Expansion and characterization of human bone marrow-derived mesenchymal stem cells cultured on fragmin/protamine microparticle-coated matrix with fibroblast growth factor-2 in low serum medium.
November 17, 2009 at 9:57 am
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| | Expansion and characterization of human bone marrow-derived mesenchymal stem cells cultured on fragmin/protamine microparticle-coated matrix with fibroblast growth factor-2 in low serum medium. Tissue Eng Part C Methods. 2009 Sep;15(3):523-7 Authors: Kishimoto S, Hattori H, Nakamura S, Amano Y, Kanatani Y, Tanaka Y, Mori Y, Harada Y, Tagawa M, Ishihara M Fragmin/protamine microparticles (F/P MPs) can be stably coated onto plastic surfaces. A capability of F/P MP-coated plates was investigated to immobilize fibroblast growth factor (FGF)-2 as a substratum to expand human bone marrow-derived mesenchymal stem cells (BMMSCs). FGF-2 molecules in low (2%) human serum (HS) medium were immobilized onto F/P MP-coated plates, and the FGF-2 was gradually released into the medium with a half-releasing time of 4-5 days. BMMSCs adhered well to the F/P MP-coated plates, and grew at a doubling time of about 28 h in low (2%) HS medium with FGF-2 (5 ng/mL), while the cells grew at a doubling time of about 30 and 38 h in high (10%) HS medium and in low (2%) HS medium with FGF-2, respectively, without F/P MP coating. The expanded BMMSCs on the F/P MP-coated plates in low (2%) HS medium with FGF-2 maintained their multilineage potential for differentiation into adipocytes and osteoblasts. PMID: 19191666 [PubMed - indexed for MEDLINE] |
| Regulating fibrinolysis to engineer skeletal muscle from the C2C12 cell line.
November 17, 2009 at 9:57 am
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| | Regulating fibrinolysis to engineer skeletal muscle from the C2C12 cell line. Tissue Eng Part C Methods. 2009 Sep;15(3):501-11 Authors: Khodabukus A, Baar K Muscles engineered from transformed cells would be a powerful model for the study of muscle physiology by allowing long-term in vitro studies of muscle adaptation. However, previously described methods either take >5 weeks to produce a tissue or use collagen as a scaffold, which decreases the specific force of the muscle, making it hard to measure the function of the constructs. The aim of this study was to rapidly engineer muscle using the C2C12 cell line in fibrin, which has a stiffness similar to muscle tissue, allowing accurate functional testing. Both the protease inhibitor aprotinin and the natural cross-linker genipin increased the length of time that muscle could be cultured, with genipin increasing the time in culture to 10 weeks. The function of the tissues was significantly affected by the batch of serum (64-78%) or thrombin (41%), the differentiation medium (78%), and the seeding protocol (38%), but was unaffected by initial cell number. Strikingly, different C2C12 clones produced up to a 3.6-fold variation in force production. Under optimal conditions, the tissues form in 10.4+/-0.3 days and remain fully functional for 5 weeks over which time they continue to mature. The optimized model described here provides rapid, reliable, and functional tissues that will be useful in the study of skeletal muscle physiology. PMID: 19191517 [PubMed - indexed for MEDLINE] |
| A practitioner survey of opinions toward regenerative endodontics.
November 17, 2009 at 3:57 am
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| | A practitioner survey of opinions toward regenerative endodontics. J Endod. 2009 Sep;35(9):1204-10 Authors: Epelman I, Murray PE, Garcia-Godoy F, Kuttler S, Namerow KN The success of regenerative endodontic procedures requires practitioner acceptance, but little or no evidence is available. The purpose of this survey was to collect the opinions of attendee's of the 2008 Endodontic Board of Diplomates 2008 Summer Conference on the issue of regenerative endodontic procedures (REPs). After Nova Southeastern University institutional review board approval, 100 copies of a survey were circulated, and 56 completed surveys were returned anonymously. The survey found that 96% of participants thought that more regenerative therapies should be incorporated into treatments. Although only 14% of participants had used umbilical cord or stem cell banking for themselves or a relative, 63% thought that stem cell banking would be useful to regenerate dental tissues. Most (89%) of the participants would be willing to save teeth and dental tissues for stem cell banking. These results suggest that endodontic practitioners are supportive and optimistic about the future use of REPs. PMID: 19720217 [PubMed - indexed for MEDLINE] | | | 
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